Potty Training Advice for a 3+ year old?

[2cuteboys]

Update to the above situation:

Dcb was doing alright until sept. long weekend - maybe 1-2 dry pants per day, would poop consistently in potty when I put him on (if I leave him on for a few minutes he tries to o something, usually resulted in a bm), for which he was getting praise and stickers, as I'm trying to reserve candy or dry/clean pants. He was still having a lot of pee accidents in his pull-up a lot.

After sept long weekend (had 4 days away), he came back and had started pooping in his pants again, even minutes after getting off the potty. He's never asked me to go to the bathroom, but generally if he had to go he'd go when he was on, as he's there pretty often.

I gave it a week or so before mentioning it to the parents. My thought was that they'd dropped the ball over the weekend and stopped trying, thus the lack of progress and slight regression. I spoke to mom about it and she told me they've been putting him on every hour at home (and he screams and cries when they do it), and have had very little success. Mom thinks he doesn't have the control or awareness to know when he needs to go and hold it until he can get to the bathroom.

I'm torn on what to do next. I've narrowed it down to two things going wrong:
1) He doesn't have the control or awareness and thus isn't ready. With a younger child I'd be inclined to take a break and try again later, but this child is 3.5 years! I've suspected slight developmental delays (have been communicated to parents, they aren't concerned), maybe this is related.
2) This is more of a behavioural issue (especially given the new info that he has tantrums over it at home). This kid has EVERYTHING done for him at home and knows that it's easier to have his bum changed in 5 minutes, then to get up, leave his toy, tell me he needs to go, and make our way there and do the whole routine.

Any thought on where to go next? I'd have very different approaches for the two, so I was hoping someone else might have some insight as to why this is happening, or what to do next?

Thanks in advance ladies! I really appreciate it!