You have no idea what you are proposing? Have you ever at by someone who was starved to death. Believe me - a feeding will be much more appealing when push comes to shove. Besides you would be requiring your caregiver to sin. It is a grave sin to withhold food/fluids from a person with intention of have them starve/dehydrate. I would not like you/he to have that on your/his conscience when you go to the Judgement.
If I was old and possibly sick, and my body wouldn't want to even accept liquid food, and I wouldn't want a feeding tube being pushed down my throat, but rather die; I don't think I would be guilty of committing the sin of ѕυιcιdє, neither would the caregiver be guilty of any crime.