At this point you may consider raising his temp to 85° and keep humidity at 80%. Higher temps can stimulate appetite as well as digestion. Raising the ambient air temp to 85° not just the warm side. You can keep him at 85° for a day or 2 while you monitor him to make sure that he doesn't react strangely to the higher temps. Shouldn't happen, but just as a precaution if you never had his temp that high before.

I'm also going to recommend a visit to a Vet that specializes in amphibians to have him checked out. If he is impacted the Vet can give you some liquid laxatives that will help him poop.

Keep us posted.