"As long as it doesn't swap it out completely like it did last time. Both Charles and I nearly lost our minds with that one." Erik never wanted to experience Telepathy again. He had no idea how Charles dealt with it, and Charles felt the same way about his powers.
"I'm sure we can find a way to make it stronger and sharper. It will just take some experimentation." Anyone who would defend Nina was his friend, and Amberle had been his friend before that so it just made him like her more.