It depends on the age and strength of the boy. Assuming he is in his early teens or younger then a ladies model golf club would work well. If he does not want to play with a ladies club, he should be fitted for clubs with a light, flexible shaft.
If he is around the age of 10-13 and is serious about golf, I would recommend a set of womens irons. They will have the proper high and shaft flex for someone that size. Power Bilt makes a good, affordable womens set.