Meanwhile, whilst considering what to do your son should be eating multiple small meals thru out the day. Easy to digest meals. Six meals a day of very small amounts vs the usual 3 heavier meals per day.
No raw fruits, no fruit skins, usually canned fruits are digestible. The same w/veggies, no raw, but rather well-cooked, soft veggies. No "gassy" veggies. Easily digested foods. Well cooked. Chewed THOROUGHLY. Eat SLOWLY. Eat only until comfortable, never to uncomfortably full. The weight loss scares us into trying to eat too much to get that weight back on. NOT the right thing to do.
A high grade partial obstruction (stricture) is most likely the culprit in foods taking so long to move thru leaving him feeling full after small amounts of food.
Just my guesses based on my own experiences thru the years. I've been living w/a high grade partial obstruction at my old resection site for 10 years now w/very little disease activity on occasion and for the most of that time w/no disease activity just the scar tissue at the old resection site.
I am NOT a good candidate for any type of surgery now due to severe COPD and prolonged anesthesia. I am on 02 24 hours a day.