12 months is small in terms of sleeping through and nightweaning, still. It probably is going to be distressing if you try to control his sleep in any way just yet. You need to either be prepared to go through that, or accept that this is the way it is for now, although there are ways of managing it. It might work for you to get a single mattress and put it on the floor in his bedroom, instead of a cot. That way you can get in to settle him to sleep and then it's easy to either bring him into bed with you later or for you to climb in with him (I used to do some hot-bedding with DS
) and then sleep there or resettle and come back to your own bed. In some ways this is easier once they can walk as they have to actually get out of bed and come and find you, shortly after starting this DS stopped bothering! He'd come in at about 5am for morning snuggles, although this got later and later until it wasn't happening at all. He's only just at 3.8 accepting being left alone to fall asleep without huge upset, but it only works if he's very tired and on the point of falling asleep.
The other thing was that at that age I found if I went out or for some reason didn't want to give DS milk he just wouldn't fall asleep in bed without it, it was like a totally alien concept to him to lie down without being cuddled up and/or having milk. I used to take him for long walks in the pushchair, and then as he got used to being in the pushchair, just being strapped in there and pushed forward and back seemed to calm him. After a while I could just strap him in and it seemed that this calmed him down enough for him to sleep. It was like if he was in bed he didn't know what to do with himself because there were all these choices, he wanted to sit up, crawl around, look over there, see what was happening out the window. Being strapped in he had no option other than to lie still and he usually drifted off. I used to put him in there while I MNed or watched TV or something and then just transfer him to bed when he was asleep. He still has to be told to lie completely still before he will relax enough to go to sleep!
If he had a babysitter (it was usually my mum) they just tended to either let him stay up until I got back, or watch some quiet TV and have a drink of milk on the sofa and then he'd normally fall asleep there. It helped if this was fairly long after his usual bedtime, but at least I knew he could do it!