Quote ABrazil: Nikki never liked Phyllis I remember many episodes when Nick and Phyllis were married and Victoria was married to Brad and Nikki has said neither of my children married well. Also when Nick got back with Phyllis the last time Nikki was against it.
There was a time when every character hated another. Everyone hated Sharon when she was with Adam, even Nick, and now they are together. Remember how volatile Nikki and Victor's relationship has been over the years. They all moved past such feelings. Victor does not hate Phyllis, he sees her as his granddaughters mother, who knows something that could destroy his son. This and his hatred for Sharon, is his only motivation in doing everything possible to wake Phyllis.
The reason Victor is being secretive about the experimental treatment, is that he feels Phyllis' family may not consent to it, which would delay his plans.