Husband broke hand in a half cast swelling getting worse shouldni take him back in?

Probably: Swelling is expected in the first few days to a week after a 1/2 cast is put on. That's why they put the plaster only 1/2 way around to make room for the swelling. Is he keeping his hand elevated as much as possible (above the level of the heart) and in a sling? This is very important. If it is also painful then more important to get it checked. Just swelling you could try better elevation + wait.