Gst input query composition dealer

No issue  , Composition  Dealer  will be issue  Bill  of supply  to registered  dealer  , No question  of  Input  Tax credit  for registered   Dealer  , But  he has show in GSTR 1  and GSTR3B . 

On your sales you will not be charging GST from buyer and therefore they will not have any ITC. You will have to pay GST from your own pocket. AS such the buyer won't be having any issue.