How Should A G6PD Child With Acute Constipation Be Treated?

I have a 3yrs old child,he was g6pd positive, sometime it takes 3-4 days for him to go in the comfort room?his stool may be big and hard that it make him difficult to make it out.I avoid feeding him foods which are not good for him.I dont know how to manage the problem,it hurts me everytime i saw him in that condition.