Okay guys, time to yap my theory. He was only 30, so his cognitive impairment wasn’t the...

Okay guys, time to yap my theory. He was only 30, so his cognitive impairment wasn’t the result of age-related conditions like Alzheimer’s. Onset of dementia-like symptoms in younger adults is usually associated with brain tumours, CNS infections (encephalitis, meningitis, etc), genetic diseases like Huntington’s, or acquired prion disease like CJD (very rare). Considering he’s still alive, it wasn’t Huntington’s or CJD, and CNS infections are usually acute and symptoms are resolved after treatment, so that wouldn’t explain his prolonged absence. Therefore, my theory is that he had a brain tumour (probably cancer) and needed to return to the US for intensive treatment over a long period.