David, (I presume?)
WELCOME TO THE AWS WELDING FORUM!!
I haven't been IN the Boilermakers Union for a good many years. But, when I was, it had an excellent apprenticeship program and for the most part I hear it is probably even better now.
I was originally in Local 72 in Portland, OR and don't know anyone out of your area. But, I have met their national President and several other current members and they all seem like pretty good people. And MOST are willing to help others.
Now, you will find some with bad attitudes and little to no patience. Many will expect you to learn quickly. Try not to over-emphasize your disability. But let them know you need repeat instructions and help to get it in place in your brain and understand it's application.
Overall it is a good program. There are others here with more recent involvement with them. Good luck.
He Is In Control, Have a Great Day, Brent