HI, My Brother In Law Has Lost ~25 Lbs In

HI, my brother in law has lost ~25 lbs in 6 weeks, had a persistent (recurrent) daily fever of ~102. he was hospitalized for 9 days, no conclusions drawn. he is ~65, was active, maybe 10 lbs overweight but no more. Any thoughts?

Sorry, I didn't realize this was a paid site. I'll dig through the literature myself. He still has the fever, I didn't mean to make it past tense. That's what seems weird to me.