How do I handle my 18yr old who is jealous of my 10yr old? ?

Most probably ur daughter feels that u don't care about her nor about ur grandchild. U said that u don't feel like a grandma...Look at the story of both parties and not only ur story. Even if u r sick, enjoy the presence of ur daughter and grandchild, and let them feel that u love them. Y don't u allow ur grandchild to enter ur room??? medications??? put them out of his reach... try to find a solution which will join u all and not disperse u. I don't agree at all that u kick ur own daughter out of ur house. What ur daughter is now, is what u made her be in raising her...show her some love and things will change.