Ain't a doc, but my first guess would be something autoimmune related to a tick bite.

Brazos- wife's boss had a rash and seemed to constantly be under the weather. Leukimia. Cancer flat sucks.

Hope what ever it is runs its course and he's back to feeling well.

Regards,
Blake

“Life is life and fun is fun, but it's all so quiet when the goldfish die.”