husband can not wake up for baby!!

Quinn • 25, wife, mother, lifeguard, college student, future RT. I like to stop and smell the roses 🌹
My husband has always been the heaviest sleeper and the hardest person to wake up I've ever met. He sleeps through alarms of all kinds. It's ALWAYS frustrated me and to some degree I've always believed he could just get it together if he really wanted to. Well...now I'm thinking otherwise.
My hubby watches baby while I get a stretch of sleep long enough to really matter; usually 5 hours or so, from midnight to 5 am. This morning around 4 I wake up to Lyla crying. I drift back asleep but wake up 15 minutes later and she's still crying. I wait because my husband feels infantized if I try to "rescue" him from her upsets when he's trying to soothe her. After 30 minutes I figured it was his pride keeping him from asking for help, so I come out. Lyla is SCREAMING her head off, bright red in the face, in her mamaroo. And who is DEAD ASLEEP on the sofa about 5 feet away?! Husband! Basically comotose! I have never seen anything like it in my LIFE.
I bit my tongue until I calmed down because now I realize he is not doing it on purpose. I woke him and he couldn't have felt worse :( even though I'm not angry and him I am upset about the circumstances. I need to be able to leave my daughter with him and now I'm not confident he is able. I realize he may not wake up to her crying. Or the Snuza breathing alarm if it goes off, god forbid. Or the fire alarm, again, god forbid...
Does anyone have any thoughts about this? I think I am going to ask him to see a specialist about the possibility of a sleep disorder...that's not being overly dramatic is it? :(