My husband hand is swollen & in a lot of pain. what is a good home remedy for it?

None: Go see a doctor. Hand pain and swelling could be multiple things. But if infection is one of them then pain , disfigurement and loss of limb or life could be at risk. Not to sound to dramatic but if he is in your age group don't mess around. It could cost a lot more in the long run.

Need to be seen: This could be an inflammatory form of arthritis. If so, early detection and treatment are proven to improve the odds of a better outcome.