My 77 Yr Old Dad Just Died. He Had Alzheimers

my 77 yr old dad just died. he had alzheimers all ofnhis organs was in perfect health. the problem was he didnt sleep so the hospice dr prescribed 150 mg of seroquel at night with a low dosage of risperdal after about four weeks he died. did this cocktail cause his death. he didnt start going down till i gave him these drugs