Newly almost diagnosed 21 year old son

I am new here and new to mental illness in my family. I am by profession a social worker who works in education with children with behavioral/emotional disorders. Ironically enough, my own son, aged 21, has psychosis and will likely have a diagnosis of sz soon. He was a college student, in his 4th year, when he began developing motor tics, high anxiety, and paranoia. I found an early intervention program for him in my community which is based on the RAISE initiative. Problem is, he is completely unwilling to submit to any medical intervention. He will not see his PCP, undergo the requested MRI and CT, submit to blood work or has been adamantly opposed to taking medication. He will, however, meet with the psychiatrist and primary clinician. At what point do I attempt to force his hand by removing his car, etc…until he complies with the program recommendations? Should I give him some time to process all of this?