Northern California Employee - Therapist

My brother works as an online therapist for Kaiser Permanente Northern California. He hasn't gotten paid for the past 5 weeks. He keeps calling his boss, but nobody seems to know what's going on. I just read that the therapists in Southern California are on strike and wonder if he accidentally got caught up in that dispute. Any insights? What does a person do in a situation like this? He's still counseling patients, just not getting paid.