merging post to another post of lower qualification

My brother was recruited by SSC for a post with BE in computer Sc and engg/Msc with 70% minimum as the criteria.the post is of 4200 grade pay.but at the time of joining due to merger of the department to another,the post has been merged to another post of same grade pay but the RR are different.yet the qualification criteria of the mapped post is diploma,the RR strictly mention BE/Msc are not allowed.The recruitment process have not mentioned of any downgrading of the post.What can we do now legally ?