John McCain has a strong negative view of this bill. Part of his reasoning for saying no is that he was just diagnosed with cancer, and the Graham-Cassidy healthcare bill, he argues, doesn’t do enough for pre-existing conditions. Who knows where cancer will be classified in this particular bill? Maybe McCain knows it’s going to be a pre-existing condition now, which is completely wrong. However, none of his reasons are personal for saying no.
In fact, he’s actually good friends with one of the authors of this healthcare bill, Senator Graham. Graham has said that, while he wishes he could have persuaded his friend to support the bill, that friendship is based on respect, not how McCain supports him. He continues to fight this bill, and most likely will continue to do so.