asalamo alaikum,so small baby u must be worried for that.1. stop all laxative drugs.2-- give him normal feed and all rice,meat bread etc.this constipation
is due to lack of water which is absorbed from faeceswhen it is stored in lower part of colon
and that become hard so ----give him lot of water, one bottle feed and other one water. ----give him one tea spoon of melted butter after each meal three times a day----wear the glove dip ur small finger with pure glycerine and dilate his anal opening once a day inthe morning before passing stool.