Basically, three main points:
1) strengthen and stabilize; don’t stretch
2) fix your habits so the area is not continually re-injured
3) treat with manual adjustments and further strengthening exercises
He gives some advice on how to find a hands-on PT who can adjust the SI joint:
Insist on someone who can do a “Grade 5 lumbo-pelvic mobilization.” If there is any hesitation in the answer, keep moving.
He says that about 1/10 physical therapists know how to do this form of hands-on work.