If your 8-year-old son has not had a bowel movement in 3 days and is experiencing discomfort or having trouble passing stools, encouraging him to drink plenty of fluids throughout the day and increasing his fiber intake through fruits, vegetables, whole grains, and fiber-enriched cereals can help soften his stools. If the issue persists and causes him discomfort or difficulty, a tasteless and odorless powder like PEG-3350 can be mixed into any liquid to help. The dosage of the powder should be based on your child's weight, and you can consult with a pharmacist for guidance on how to measure it. Hopefully, these suggestions can be of help to you. Feel free to ask if you have any other questions.