My SW-CAH son had constipation problems as well.  I tried to make  a habit of always giving prunes and apricots daily and limit bananas.  Occasionally we would give him a glycerin suppository.  When old enough for juice, apple juice will also soften the stool- but not a good habit long term because of the sugar and tends to fill the tummy and not get the good nutrients in.  This continued off and on until he was probably 3.  The good side was I could dump his stool in the toilet before throwing away his diaper!  His were always fairly firm.  However, you do want to try to watch his diet and as he grows older, make sure that passing a movement is not a painful time.  Otherwise, he will try to keep it in  and make the problem worse.  I forget how many months you said your child was- but the rice cereal can be firming, too.  For diarrhea, we were always told to follow BRATY-Bananas, rice, applesauce, toast, yogurt- to firm things up.  So, do the opposite!