Suggest Treatment For Severe Constipation

Hi There My son is 8 years old, has had history of constipation but outgrew it after 4yrs old. He was sick about 2 weeks ago and his system has seemed off, he hast had a bowel movement on thursday, usually goes every other day. Since Sun having trouble, keeps trying, I gave him chewable laxatives yesterday and today , did a glycerin supp yesterday , was going to do fleets today but he is scared and not letting me. Tomorrow will be six days, do not know what to do. I know the dr office will tell me to do a fleets enema and did not want to take him there,