do you see a lump near his tail? If he is impacted he will have a distinct lump and swelling. It's unmistakable and it feels like a marble inside the snake. If you don't have any of that going on, I would stop worrying and leave him alone as massaging poop out of a snake that doesn't have to poop is probably very stressful on the snake. They don't necessarily poop every 3 or 4 days.