At present I can only think of my sister's last few years, with the constant and relentless worsening of her mental and physical condition. Sentiments such as it being "a merciful release" fail to acknowledge the human cost and the suffering of the person afflicted, and of all the family members.
During my husband's last few months of life I witnessed and coped with his physical and mental deterioration. It is possible only to deal with the situation little by little, day by day, and as events unfold, and as necessity dictates, reacting to developments and deterioration little by little.
My sister will have a loving and heartfelt farewell, from her immediate family, sisters and brothers, nieces and nephews, and many friends. Thus lives and loves are acknowledged, celebrated and remembered.