Hello, I'm Dr. Deb. I'll do my best to help you today.
This is obviously a really touch situation since it does sound as if he might be obstructed from the diaper he ate.
I'm not absolutely certain if laxatives will be helpful but it might be something to consider. The following are what I'd suggest:
1. Canned pumpkin (NOT the pie mix); 1-4 tsp daily in food for small dogs. Squash can be substituted for pumpkin.
3. Miralax 1/4-1/2th tsp twice daily
bran flakes (wheat bran, not the cereal) at a dose of ¼-1/2 tsp daily
5. Psyllium (Metamucil®): Doses vary but typically a suggest 1 teaspoon (tsp) of metamucil per 10 pounds of body weight per feeding
mixed with food once or twice a day.
I'll be honest and say that I've not been universally successful in getting laxatives to work in this type of situation but they shouldn't be harmful which is the most important thing.
I hope this helps and that you are successful in getting him to pass the diaper (if that's his problem). Deb