Potty training

Ever since Conlan was about 2 years old, we've tried potty-training him. Success varied. Sometimes he would release in the morning after setting him on the toilet. Sometimes he seemed scared of the toilet and bathroom. Sometimes (forgive the pun), he just didn't give a crap. Being used to training dogs in about two weeks, I think we gave up for the most part.
The local school district hosts a monthly ABA workshop for parents. Last Fall, I was able to go to a couple. One was on potty-training. Having never successfully trained a human child, much less an autistic one, I learned a lot but wasn't around Conlan enough to implement some of the ideas and suggestions. So we continued down the same path.
Four years later, he is still in diapers. Sometimes he'll sit on the toilet. Sometimes he refuses.
While he was going to summer school, he seemed to make a lot of progress. He started changing his own diaper! He'd go off all by himself and return with a fresh diaper, sometimes on backwards. Independent is this boy! After that, we thought he was ready. So, this past Saturday, we bought some training underwear and stopped using diapers.
It has been very difficult. To get things going, we decided to put him on the toilet every half hour. It went well, except he would wait until after being on the toilet to let it go. Sometimes mere seconds after getting the underwear and pants back on. Argh! He quickly learned the process: take off pants, underwear, sit on toilet for a while, get off, flush toilet, wash hands, dry hands, put on underwear, pants, socks and shoes and go play. Now when we just take him to the bathroom, it's almost automatic with a lot less prompting. He also seems to be sitting better, and not just on the toilet but at the kitchen table, in the car, at school, etc. So although we haven't had much success, he's learned a lot and made lots of progress in other areas.
And it's only day 4. Patience, Evan. Patience. I need to realize that he has been wearing diapers for more than six years. He's used to taking care of business on the go whenever and wherever he needs to. Why hike up the stairs to the bathroom and go through all the hassle? The alternative is so convenient! He's used to the wet feeling against his skin. It'll take some time, patience, consistency, and courage from all of us.