回複：H1B transfer denied, please help.

it is fine as long as he has kept working for A for the 3 months. if he has already left A for B, it is a problem.

what's the reason of denial?

position not qualified as "specialty occupation"?
he does not have the required degree/experience?
pay not >= prevailing wage? or something else?
he may be able to appeal depending on the reason and his particular situation.