Can an employer refuse to adjust work start times that keep you from attending physical therapy?

My fiance was injured at work about three months ago. He filed a claim through work and was approved. He had significant damage done to his right arm which required surgery and physical therapy. He returned to work with restrictions stating that injured extremity is to not be used at all. He has complied with every ridiculous job they have given him including writing invoices with his left hand (he's right handed). He is required to attend physical therapy two to three times per week. They have his work day starting at 9:30 am, and ending at 6:00 pm. The physical therapy providers take last patient at 6. He asked if they could adjust his start time for one hour and refused. They had no reason, it was just because I said so.