He will urinate in public restrooms and in our toilet 99% of the time.
In the last three months however, we have only been able to get him to
poop in the toilet twice. He will have a daytime accident about every
7 to 10 days. The rest of the time he seems to be on some strange
internal clock where he only will go at night in his sleep every other
day. We have tried high fiber diets, laxatives, etc. The only thing
that manages to accomplish is that he is VERY messy the next day and
needs a very thorough cleaning in the morning. He says he is not
afraid of the toilet, and that he wants to do it. He tells he will
start using the potty, and that he will quit having accidents.

Are you sure it's not the laxatives that have actually caused the problem? A
friend had this problem with her twins, they both at various times were
struggling with constipation, so the doctor prescribed laxatives and they
suddenly started having poo accidents, fortunately she realised fast an no
long term harm was done. I would definitely take him to the doctors, pooping
whilst asleep doesn't sound normal to me, at least my kids have never done
it right from birth, they were awake or feeding when they pooped.

Anne