Telling a 5 year old that one day they'll die? Help!

[GlitteryFluff]

A family pet died today.

Ds who is almost 5, is ok. I've explained he was poorly and very old and the vet couldn't save him so he's died. Then I stupidly said he's gone to heaven to soften it a little. He's asked to go to heaven (to see the pet) and I quickly said 'one day, maybe' (what kind of answer is that?!) and sort of moved the conversation on (still talking about pet but not about heaven). Ds doesn't know yet that everyone dies one day. He's talked about living to 100 or 1000 and asks how old I will be when he's 1000 etc and I feel like I've got myself in a pickle because I've always said oh I don't know that's too hard to work out - should I have been telling him that I won't be alive by then (and neither will he?)
Or is he too little?
I don't know how to tackle it.
Should I be saying yes you can visit him in heaven when you die but that won't be until you're very old and have had a good life or do I just keep side stepping it and hoping he's a bit older when he has to be told or twigs himself?
We've luckily had no human deaths in the family so this is his first experience of death and my first death in parenthood.
I'm honest with lots of other things and feel like an age appropriate version of the truth is usually the right thing to do but this doesn't feel right. I don't want to break his little heart - I'm getting upset at the thought of him realising that I will die one day and he will die one day too.
Do I start breaking it to him gently so when he next says about living to 1000 do I say people don't live to 1000 as their bodies can't grow that old (or something?) and see where the conversation leads? What do I do?

I’d have said that all living creatures die. Sometimes because they get really sick and sometimes from old age and sometimes even from an accident. As for where they go, heaven is fine but explain that only dead things can go there. I think he can understand that at 5.
My children’s father died when they were 4 and six. I couldn’t sugar coat it. I said he was in heaven but would always look out for them. He actually didn’t believe that and I’m not sure if I do but it seemed to help.

We got a great book called Lifetimes about the life cycle of plants, then animal and them humans and explains that when a creature becomes too old or get too ill for its body to work any more, it dies. Children usually accept simple truths. There will be moments of sadness when they realise that granny etc will die

I showed a pick of my dad to my 3yr old. I said he was dead. 3yr old said "and Grandad is dead" (daddy's dad), which he is. 3yr old then said "and Granny is almost dead". This is how Daddy had explained it.
Granny has terminal cancer and probably has less than a year, so in reality, it was probably a pretty good description for a 3yr old, even if it did surprise me a bit!

I think there must be some great books out there that can help with this. I just don't have any suggestions myself

Hopefully more MN folk will be along to offer suggestions...

Thank you all. It's such a tricky subject to tackle and I just feel he's too little for me to break it to him right now. But then I worry someone else will break it to him in the wrong way so I should just do it when he next mentions death/age etc
I feel like going down the all living creatures die route and that everyone meets up at heaven when they die so it's not scary.

Going to look up the book suggested thank you.

DD has always known,my dad died when she was a toddler so whenever she asked I told her he died and he is in heaven and loves her and watches over her. Then we had the conversation of everyone dies,but you won't for a very very long time, no neither will mummy, no not daddy either... ermmm the hamsters might in a year or so, you get the point.

I’ve just had this conversation with my 4 year old. She was aware that animals died but I think she’s only just realised that people die too. I’d never really told her as such, but one night she was in bed crying saying she was worried about what would happen to her special cuddly toy when she died. I was taken aback as I had no idea she’d joined the dots like that (we’d also been to see a very ill friend that day and I think she’d overheard things). I just said everyone dies, usually when they are very old but sometimes younger people have accidents or get very ill and die but it’s very rare and she shouldn’t worry about it until she was very very old. I also explained that no one would want to live forever and most people don’t mind dying by the time they are very old. That was totally winging it but she doesn’t seem to have had any more little worries yet. I wouldn’t mention the fact that you will die, I don’t think they need to dwell on that at this age and I don’t think they can even imagine mum not being there as a concept really.

I’ve just had this convo with my 3 year old when he asked where my FIL’s parents were. I said everything dies eventually. Flies only live for a few days. Dogs and cats and birds live longer but not as long as people. When you’re very very old and you’ve had a long happy life you get tired and your body gets stiff and you just want to lie down and go to sleep and then you don’t wake up. But you are never really gone because all the people who love you still remember you and they can talk about you whenever they want.

If we had family illness or anything more imminent going on I’d have to adapt it obviously! It seemed to satisfy him for now but he has since wanted to go through it again so must still be working it all out.

I am really hoping he is not going to be terrified though every time I say how tired I am! It’s a minefield!