Have just looked this up. (I've had trouble with this in the past and, because my DH is the music lover, I have made him the family organiser so he shares his purchases with me. We store a credit card with Apple but have used iTunes cards too, you can tell Apple which of your cards you want it to take payment from.)
The advice I've given you about Apple family sharing is correct as far as it goes. However, your DH will have to set up his own iTunes account and redeem his card (i.e. put credit on his account) before he tries to make any purchases and then manage his credit himself. I can't find out if he can share his purchases with you under these circumstances, although, if he runs out of credit, any purchases he makes as a 'family' member will come out of your card and then you both can share them.
As to photo sharing, it is very simple to 'Airdrop' photos between Apple devices, again I suggest you Google 'Apple Airdrop photos between devices'.
It's never really simple is it?