G.B.
Joint custody is a bad idea. When no one has legal custody they can't make ANY decisions without the other one being in agreement. IF she says yes and he says no then it's a no since he won't agree. If she has custody she can make the decisions when needed.
If they both have custody and he doesn't like the child care provider then she can't leave the kids there, if he wants to come pick them up every day and feed them ice cream with chocolate syrup right before dinner she can't do anything about it. He has that legal right.
If they both have legal custody only one gets to file the kids on their tax refund, no one pays child support, no one has legal authority to do anything. If he takes the kids to live with him she can't do anything. He has that right.
It only goes on and on.