Pressure sore?

Well, you are not helpless. It is of some help to listen to your guy complain. A limited amount of complaining is normal and what fun is it if no one listens? Secondly there is nothing 'normal' about a pressure sore showing up the size of a baseball.  I would go to an infectious disease doc quickly. He is likely to be on bedrest for quite a while.

I'm surprised that his mom is not alarmed. The Reeve Foundation has a link where you can ask questions and a regular  question and answer with an SCI nurse. You can find that here:

www.christopherreeve.org/get-support

Their blurb about pressure sores is here: www.christopherreeve.org/living-with-paralysis/health/secondary-conditions/skin-care

New Mobility is a reliable source of information:   www.newmobility.com/?s=pressure+sores

While you are not currently facing a wound that won't heal here is an outstanding article that surveys the latest treatments doctors may not know about yet:   newmobility.unitedspinal.org/NM_Oct_18/#?page=38
Keep it in your "favorites" list.

While I understand that neither your friend nor his mom seem alarmed this should be taken seriously.  Does he keep a file of photos of previous skin problems? Everyone should. Take a few pics on your phone and show them to him if this has not been done. After all, he is in charge.  Place your hand in the pic for a size reference.  Keeping good photographic records of all my problems, be it skin or strange things in my urine, has helped gain me more respect from my doctors. They do not trust what I tell them but photos and careful written records impress them. it's the kind of data they trust and I never know when my records are going to be really important to my treatment.

That's good news that is smaller. I agree this should be taken very seriously, do not use a donut but keep all the pressure off. I fought an open sore for a year before having flap surgery with 5 weeks in the hospital. Dinner and a movie are always great and board games can be a good way to pass time.