My Friend Is Suffering With A Torn Meniscus And ACL

My friend is suffering with a torn meniscus and ACL in his knee. His doctor first gave him a cortisone shot, and prescribed therapy, without any improvement. Next he has gotten 2 (of 3) gel injections into his knee. Over the last week or two, everything else has started to hurt. First a shoulder and arm, now the other arm, too. Aching and muscle weakness. His is diabetic, type 2, and taking oral medication.
What's going on? He is completely miserable and can hardly get in and out of the car.