my dad recently passed away from alzheimer's disease. During a 5 day period (when i was on a trip and no one visited him) he slipped from

stage 5 (able to dress, feed himself with supervision - but unable to recall personal history reliably; lack of current info) (lasts approx 1.5 years)

to stage 6 Agitation and hallucination, loss of bowel & bladder control, inability to do independent living tasks; responds to nonverbal stimuli

and in 2 weeks he was at stage 7: Loss of speech, moans only, no ability to ambulate, no swallowing ability - required total support
he was in stage 7 for 3 days and then he passed away.

Has anyone else seen such fast decline ?