Both of my daughters slept on their belly from birth even now they still do. I just checked on them constantly and not use many blankets

Then it's fine to leave him that way. But make sure you keep an eye out for him. Check him frequently . They sleep deeper this way so you might have to wake him to eat.

@jaixi, yes he can turn his head

I stop putting my baby On her back before two months. Because she wouldn't sleep. But she could turn her head on her own.

Can he turn his head?