Sleep deprivation

I am currently dating a firefighter and sometimes after shifts he is completely exhausted and not in a functional type of mood and I get that shifts can do that.

He also has a part time as well that he goes to at times right after his shift. We aren’t married yet or anything or have kids but I’m thinking about the future and that makes my anxiety rise. Today he got off his part time and went home and fell asleep at 4pm and is still sleep past 10.

How will he be able to function when we have a family or kids? He says that if we had kids he wouldn’t have a choice but to be up but that doesn’t ease my anxiety and he mentions I come off as naggy or projecting my anxieties onto him but these are justifiable thoughts

Trying to get advice on firefighters and firefighter spouses on how they’ve navigated family, spouse etc