My Husband Was Diagnosed With Whipples' Disease In 2011. He

My husband was diagnosed with Whipples' disease in 2011. He has since developed dementia after two strokes and several TIAs. He was never treated with sufonamides (due to type 2 hypersensitivity to sulfas). He has been maintained on doxycycline continuously. He's quit smoking, has type 2 DM with AIC = 7.0. He does not exercise vigorously due to CHF. He had a right BKA in 2014 due to nec fasc and gangrene post-bunionectomy). No one has verbaized the cause of the mental deterioration. I suspect it is multi-factorial. My question is this: are there other potentially treatable entities or therapeutics that might help slow his mental decline?