How to coparent with a newborn?

My bd and I aren’t currently together. He coparent with his first wife and has his teenage daughters once a week. He wants to do the same with my 2 month old but he rarely takes care of her and never has done it alone. He works a lot so he sleeps a lot which means during the days he has his teenage daughters they’re usually doing their own thing. I always encouraged him to take them out and do things with them so I’m scared he won’t realize what my baby needs. I’m scared he’ll make them take care of my baby. Or if he falls asleep and not realize my baby needs attention. But I can’t not let him see his daughter so how do I go about this? How do I get comfortable letting him take my daughter when I have her all day every day?