What Causes Severe Knee Pain After An Injury?

Question: Have son 38 yers old. Ex wife committed suicide 3 years ago by hanging herself after being reeased from a rehab unit for Bi Polar and alcohol treatment. Left with 2 kids now 12 and 17. Married again and had 2 boys age 4 and 5. Divorced last week. Toxic relationship. 4 weeks ago played basketball and fell hurting his right knee which swelled up and large man fell on his feet somehow and they swelled and he was unable to walk and in great pain. His back hurt and his left wrist hurting (had broken wrist 10 years ago and had plate placed with screws. Hands weak, feet still bothering him, unable to walk without crutches and using wheelchair. Been to ER 4 times in last 3 weeks. Twice by ambulance. x-rays were negaive for fractures, MRI done on right knee - see ortho doctor on Monday. He has lost about 50 pounds since February. His thighs and calves have lost muscle and his face is gaunt. He had Toradol injection twice which helped some, had RX for hydrocodone and tylenol #3 did some good, got Prednisone 20 mg 3 daily for 5 days. This seemed to really help for awhile but then pain unbearable and he couldn't get up to even go to bathroom. Using urinal. Denies using illegal drugs but had a history a couple of years ago. Has no PCP because he's not usually sick (went to ER for pneumonia several years ago and had the wrist surgery 10 years ago) Has no insurance until after January 1, 2018 then Obamacare. Why is he having so much pain in his feet and joints after this long. I'm really worried about him. He's not working and has 5 kids living with him. What could be wrong and what could help him recover quicker? He's been taking Ibuprofen 800 mg 3 - 4 times a day for pain. He did get an IV on the 23rd and he said that helped some. He hasn't been eating much since he hasn't been able to cook and I can't be there 24/7 due to fx of right foot and recovering from massive rotator cuff injury and surgery. Now he's thinking he has a parasite or something. I need to know what we can do to help him.