Vocational Rehabilitation Funding?

My boyfriend is going through the vocational rehabilitation program because of a bad knee and severe bipolar disorder. His knee has kept him out of work for several months due to his inability to get to work after we had a problem with our vehicle. The walk to the bus stop killed his knee and he had to quit after some time. The thing is he just went to the doctor through voc rehab and the doctor told him there was nothing wrong with his knee. The thing is we KNOW there is something bad wrong with it as he can not walk without a limp nevertheless walk for long distances and can sometimes not even walk at all. 2 years ago a doctor told him he needed surgery on it. I am curious about the funding towards voc rehab because my boyfriend def got a feeling of the doctor just not wanting to deal with his problem. Is voc rehab paid per person and "case solved"? This would explain them just wanting to tell him theres nothing wrong. Will voc rehab allow a 2nd opinion? I'm quite distressed.