Cried for 90 mins

Lower sleep needs perhaps? Depends on his nap and what time he went to bed. Let's say he had a 2 hour nap and went to bed at 7, he could very easily be fully rested at 4.

Are you sure you were asking for advice? Because you only seem to be paying heed to the rare posters that agree with you.

Have you try white noise?

As others have said you won’t get much support on here OP but mine are like yours and won’t sleep in our bed. For us when it takes more than a cuddle and a bit of soothing we try to redo the bedtime routine for us this is milk, story and teeth then back to bed. Usually they go back to sleep. I think it’s ok to leave them to try and self soothe for a short while.

By giving them a phone to watch?

Oh no, you wouldn't encourage a wake time that early! Nobody would! Presumably the OP's child doesn't usually do this, and in that case if you've tried your best to get them back to sleep and it doesn't work then you need to get up with them. As a rare thing it's not going to teach them any bad lessons. If it was happening regularly then you'd need to try and identify the cause e.g. too much day sleep, too early a bedtime etc, and work on giving them enough sleep pressure to sleep at night. The solution wouldn't be to leave them to cry for an hour every morning until they learn to shut up.

No, it's not OK to leave your 2 yo unattended because they are inconvenient at that moment in time.

What time are you putting him to bed? He's clearly not tired at 4am, so you are probably putting him to bed much too early.

Why wouldn't he be tired at 4am?

It would be a long, miserable day if he was allowed to get up at 4am and start the day when it's still night time, especially if he had a full day of nursery ahead with no naps.

I'm sorry it was so long and difficult for you. I think you did the right thing by not going downstairs, but you may also have rewarded him for crying in a way that means it might persist. I don't blame you but I don't want this to be your new normal.

There is a controlled crying method that can work but it needs dedication. You let them cry for a minute then go into the room and settle them matter of factly: it's night-time and we need to be in bed asleep. No cuddles or picking up. Then you leave and close the door.

The next time you wait two minutes and do the same. Then you can increase the wait by a minute every time or double it. You keep going in so the child knows you will come, but you lengthen the time between visits. And you always say the same thing.

I saw this on The House of Tiny Tearaways. One time it took a lot of doing this - over 50 times, but it was less the next night -15 times - and only once the following night and then they slept through. But you can't change it or stop it or you're back to the beginning.

It is how they learn to sleep on their own. They get the attention so if it's serious you are there to respond, and they know you will always come.

I hope you can get some peace with him.

What should the toddler do if he can't go back to sleep because he isn't tired?

Well @draft123 I guess you're starting to regret posting on here ! Some people are so judgemental - they can't give advice, they just want to put you down.

I had this problem with my daughter too. At that age they have to learn to put themselves to sleep (rather than the involuntary collapsing due to tiredness), and some find it difficult.
I never let my daughter into my bed (unless she was ill of course), and I never let her go downstairs in the middle of the night (maybe 6 am at the earliest).
I did spend a lot of time walking up and down with her in my arms saying over and over it's nighttime, you need to be in your own bed, you bed is your safe space, etc. Basically she had to learn that there was no alternative.

I don't think there are any hard and fast right or wrong ways to do this. Most parents muddle through doing whatever works for them. But fwiw I don't think you did anything too wrong.

And what should the 2 year old do if they are not tired and can't sleep? Stare into space?

I don't ever leave young children to cry. If I was crying I would want to be comforted.

Sorry - not sure why my phone has posted that multiple times

She took him out of bed and gave him a phone to watch… hardly says ‘it’s too early to get up’ does it?

FWIW I’d have probably just gotten up but equally I think it’s perfectly reasonable to try and settle the child back down etc. even if that means they cry for a bit. However, the OP totally mismanaged this and it was to her child’s detriment. Very confusing for him to be gotten up, given a phone and then expected to go back to sleep because now apparently it’s not time to get up.

She took him out of bed and gave him a phone to watch… hardly says ‘it’s too early to get up’ does it?

FWIW I’d have probably just gotten up but equally I think it’s perfectly reasonable to try and settle the child back down etc. even if that means they cry for a bit. However, the OP totally mismanaged this and it was to her child’s detriment. Very confusing for him to be gotten up, given a phone and then expected to go back to sleep because now apparently it’s not time to get up.

She took him out of bed and gave him a phone to watch… hardly says ‘it’s too early to get up’ does it?

FWIW I’d have probably just gotten up but equally I think it’s perfectly reasonable to try and settle the child back down etc. even if that means they cry for a bit. However, the OP totally mismanaged this and it was to her child’s detriment. Very confusing for him to be gotten up, given a phone and then expected to go back to sleep because now apparently it’s not time to get up.

She took him out of bed and gave him a phone to watch… hardly says ‘it’s too early to get up’ does it?

FWIW I’d have probably just gotten up but equally I think it’s perfectly reasonable to try and settle the child back down etc. even if that means they cry for a bit. However, the OP totally mismanaged this and it was to her child’s detriment. Very confusing for him to be gotten up, given a phone and then expected to go back to sleep because now apparently it’s not time to get up.

She took him out of bed and gave him a phone to watch… hardly says ‘it’s too early to get up’ does it?

FWIW I’d have probably just gotten up but equally I think it’s perfectly reasonable to try and settle the child back down etc. even if that means they cry for a bit. However, the OP totally mismanaged this and it was to her child’s detriment. Very confusing for him to be gotten up, given a phone and then expected to go back to sleep because now apparently it’s not time to get up.

She took him out of bed and gave him a phone to watch… hardly says ‘it’s too early to get up’ does it?

FWIW I’d have probably just gotten up but equally I think it’s perfectly reasonable to try and settle the child back down etc. even if that means they cry for a bit. However, the OP totally mismanaged this and it was to her child’s detriment. Very confusing for him to be gotten up, given a phone and then expected to go back to sleep because now apparently it’s not time to get up.

Which is why you teach them that it's still night time and not wake up time.

He's 2, not a tiny baby.

I suspect toddlers also take direction from their parents. If my toddler woke up at 4.15, and there were many times when she did, we did not give up and go downstairs. Our day started between 6 and 6.30 so if she woke that early we checked she was ok and, if she was, we did not talk or play with her, lights stayed off. If she cried because she wanted to get up and play, she had one of us as a reassuring presence either in bed with her or on the floor with a hand on her, but we did not get up with her because night time is for sleeping. It’s ok for a toddler to cry because they are not getting what they want. We got her a gro clock from a very young age so that she could tell for herself when it was ok to get up and it worked.

She is now 7 and a naturally early riser but the rules are if she wakes before 6, she stays in bed because resting is as good as sleeping. After 6 she is allowed to get out of bed and play in her room quietly and at 6.30 she can come and get one of us up. She is a happy, well rested child and we have never had sleep issues with her because as a house we have good sleep hygiene. So many kids in her class still have issues sleeping and I have to plaster a sympathetic smile on my face when I listen to the parents describe sleep habits that are the direct result of their kid being unable to sleep well.

So many crap parents on here.

No, that's why you say to them, it's not morning yet, this is sleep time.
Things like gro clocks are great for this.

If you encourage a child to have a persistent wake time of 4am they are going to end up always tired in school every day in the afternoon and not able to make it through their dinner. Children this age need probably 12+ hours of sleep and they aren't going to get that getting up at 4am, unless you plan to put them to bed at 4pm.
Sleep is hugely hugely important to a child's development and a 2 year old regularly getting up at 4am will end up chronically overtired, so no, you don't let them do it you teach them this is night time and they need to at least be resting in bed.