Welcome to you both

so sorry he has not been diagnosed yet. not knowing can be really frustrating.

I would look to alternative medicines at this point. knowing that he does not have many dreaded diseases is a plus, but sounds pretty devasting to him if he's going downhill right now.

I would inspect his environment a little closer. Maybe even move him out of his room into a more sterilized setting.

Right now, I'm looking into trying catcus juice, to rid the body of impurities and inflammatories. All natural and from mother earth.
Here is the link http://www.sonorancactusjuice.com/

I sure hope you find some answers soon and he starts his road to recovery.

Congratulations on completing high school. That is commendable.

See ya around.