Gambling addictions make people do crazy things like telling lies just to get money to feed their hunger. In this case, since you do not know if the person truly wants to use the money for the purpose he told you, I'd advise you to find out more from a closed relative or friend before releasing the money. However, If the money is intended for hospital bills, school fees, house rent or upkeep, you can send it to the wife if he's married.
I don't think the money was intended for any of those bills you mentioned, it's probably for gambling because if it was for any of those important needs, I assume he would openly tell his brother what great needs he wants the money for and that one might not hesitate to give him the money since it's for something important. Although, if peradventure you are right in your assumptions, I also support that he should give the money the man's wife.