McCain's son says of his dad, 'I tongue-and-cheek describe him as a cockroach. He is very tough to kill'

Jack McCain says his dad 'has an indomitable spirit.'

"He is a tough old person," the Arizona lawmaker's son told The Arizona Republic this week. "I usually use the term 'bastard.' He's a tough old bastard. And he has an indomitable spirit. It is impossible to keep the man down."

Jack McCain, 31, a Navy lieutenant and helicopter pilot, told The Arizona Republic, "The diagnosis he has is not a good one. But of all of the things that have happened in this man's life, of all of the times that his life could have ended in the ways it could have ended, this is by far one of the least threats to him and that's kind of how he views it."

He continued, "He's very sober about it. He understands the implication and the weight of it. But for not one minute has he let that take over his feelings towards how hard he has to fight. He is more than double my age and can outpace me in almost everything. So I have absolutely zero doubt that this is something he can not only beat but conquer."

Jack McCain said he speaks with his dad daily, and since they're both military men, he jokingly said it brings out their competitive nature.

"Every time I talk to him he sounds better than the day before. We talk about my assignment, how he's doing, the next family vacation, how those damn helicopters. He was an attack pilot, I'm a helicopter pilot, there's a rivalry there."

And the McCain patriarch isn't concerned about his mortality, says his son. "He is very cognizant of it but it's not a driving force in the way he views his particular disease," Jack McCain said. "I tongue-and-cheek describe him as a cockroach. He is very tough to kill. He probably would be the first one to admit immortality is a fool's errand. He is nothing but a man."