My Son Drove Himself To The Hospital Emergency Room In

my son drove himself to the hospital emergency room in January 2016 and was diagnosed with pancreatitis. he progressively got worse when 1 stone was blocking his bile duct. he was treated for 7 months for his illness and during that time he became unresponsive and almost comatose. his mental status was not treated and his mental state became worse, not knowing month date year birthday etc. he was discharged after 10 months to a nursing home for long term care. now unable to care for himself, no control over bladder or intestines. I have brought him home and caring for him but dont know how this could have happened from having a severe case of pancreatitis, is this a normal or common thing.I