Ds worried about me dying

[BabiesAreLikeBuses]

Ds, 5 but v verbal (ie doesn't shut up from sun up to sun down) had major meltdown at friend's house today and proceeded to kick heavily the doors on her brand new expensive house. I removed him from the house, we ended up going for a 'calm down drive'.
During this he cried lots about what he had done and the names he had called me and gulped that now i wouldn't love him any more and i'd take him home and leave him there alone. He has never been without adult supervision. I reassured him of course that i loved him even when he played up and asked if he was worried about me leaving because daddy did (he has struggled to verbalise this, xdh left just before xmas). He sobbed and said yes, daddy had left and if he was bad i might leave. I reassured again. He then said but i would leave him one day when i died and he was worried about that. He's into maths so i told him that (all being well) that was years away, 80 on average. He calculated how far off i was and his age at that point and was clearly stressed out.
How would you deal with this?
I didn't want to get too bogged down in the death bit so ended up telling him stories about my great grandma who lived to 92...

Babies i could have written your post, my ds who is 5 said something very similar to that to me this week. He has been so angry with me, and has been saying i am going to leave him or die. I used the great grandma story too... i have also been just holding him tightly when he gets this angry, and the anger turns into tears. I think he just needs to get all the emotion out.
Has your ex spoken to your ds properly about anything? Mine has left most if the explaining to me, and i think this has made the situation worse. My ex also feels that we should all be over this by now as it was last october that he left and he already has a new gf and baby, but it has taken ds longer to actually express how he has been feeling.
Sorry i don't have any actual advice, i just wanted to say i think you dealt with this really well.

Thanks potato it's good to know he's the only 5 yo with big worries. I think mine also needs to get the emotion out and doesn't always know how, his twin sister has handled it so differently, much more emotional at first, tons of questions... But explains how she feels well and comes looking for extra cuddles when she needs them - usually at bedtime.
Actually xdh was the one who did the explaining - i'd put it off as i knew i wouldn't get through it without crying lots and didn't want to burden them with that. They asked him bits but within a day were back here. He has always worked away so it wasn't an upheaval in the day to day stuff.
When you say last oct do you mean less than a year? That's fast to get new gf and baby, no idea how you have coped with that. Ours is confusing as there is no ow (as far as i know) and he has had a breakdown and decided h couldn't cope with the path his life was on and that he had nothing left to give.

It must be an age thing-dd is also 5 and has been crying a lot lately about me dying and leaving her. Unfortunately, me saying that is ages away has led to her working out her great-grandma is old and might die soon. Haven't really been able to say much about that as she is 82.