First - my prayers go out to your brother in law and your family
I am no doctor - but many years ago a man I worked with had a son that was very close to death - similar symptoms I believe.... baffled the heck out of their Dr.s in Philadelphia as well, a nurse was talking to the sibling one day during a visit to the hospital and the sibling told the nurse about their new parrot. The Dr. in the room heard the conversation and immediately said you have a new parrot - - found out the parrot had some weird tropical parasite that had transmitted to the sick boy... they then took appropriate action - saved his life. I'm not saying this is what I think - but consider anything that he came into contact with prior to sickness.
Best wishes to a recovery.
Your vision is not limited by what your eye can see, but what your mind can imagine.
Make your life count, and the world will be a better place because you tried.
"Use the talents you possess, for the woods would be very silent if no birds sang except only the the best." - Henry Van Dyke