Honestly, in regards to money.... I would do two things.

1) I would make sure that they each have a separate account along with their joint account. When paycheques arrive in the joint account, most of it should be put immediately into your mom's (enough for all expenses and savings). "Free" spending cash should be left in the joint account, and some of it put into your dad's (and some into your mom's).
2) I would see if your dad would cancel all of his credit cards, and have the only family credit cards put into your mom's name. Then he has no access to them, but if they're needed for family things your mom can do the purchase.

That way he is being responsible for the family's money by not having free access to it. If your mom is responsible with money, then she should really be in charge of it so that he has no way to access them (but leaving the free "spending" money in a joint account is fine, as it's the spending money that it's ok if he ends up blowing it all). He might not like it, but once he's calmed down he should realize that what he did was EXTREMELY risky to your family and that until he has shown a LOT of self-control and a good response to the right meds, he should just not have that access.

I wouldn't discuss it until he comes home from the hospital, because he's in a really fragile place right now.

I agree that there's no point in calling the casinos - they wouldn't do anything anyway, because as long as they get money they don't care. And their employees aren't going to keep an eye out for someone who is going to spend a ton of money.