I am in UK on a Tier 2 visa and has visa until 02nd July 2013. My husband is in India and he got my dependant visa last week. His brother is going to get married in May. Is there any problem if he comes to UK after his brother’s marriage in May?

No, there is no problem if he comes after May. There is no requirement in Tier 2 dependant visa that he should come within a particular time. He can come at any time within the validity of his visa as long as the marriage is subsisting.