you know it worries me a lot, not eating and not pooping for 3 weeks, you're on a right track with honey baths, make sure they're warm, feel right and left side, while in a bath gently massage his left (looking from a top when a frog faces away from you), just a little bit very gently massage cloaca too( go around just a few times, very very gently) , check if it swollen, can you take pic of a frog from top? it is bloated probably too.
keeping on cricket diet and locusts, both have high chitin content and can be a cause of impaction if fed exclusively. right now you need to make sure he is all right, pooped and start eating again. your husbandry has to be spot on. honestly if i were you I'd take him in until he is better and after have a good chat with your friend about husbandry and feeding pacman frogs
7-8cm is about 3" - that is juvenile male size, he should be eating every day, unless he wants breaks between feedings and variety of foods, supplemented accordingly.