LHA - under 35 - menatl health issues

I have tried to challenge a decision to reduce a clients benefits to shared room rate following withdrawal of his middle care DLA?, client has serious mental health issues, it is not practical or safe for him to be sharing a house. NIHE state as not in receipt of DLA cannot consider request?, I felt they had done this in the past for a schizophrenic client?, any suggestions on potential scope to challenge would be appreciated
Phil

Thanks for your help he is getting some DHP but still struggling, hopefully appeal will be sucessful.  However a lot of persons in this group not in receipt of dla or under a public protection order still are prohibeted for shared accomidation due to their mental health!