You cannot ask מחילה from a שוטה
If one sins (wrongs)
against someone, wholater develops Alzheimer's, Dementia etc.
According to Rav Elyashiv Zt"l you must wait
until he dies and go to his grave with a Minyan
to ask מחילה.
Once the נשמה separates from the גוף he is no
longer a שוטה.