There is if he doesn't cast a vote for Kavanaugh, even if Kavanaugh is confirmed without him. He needs to hear from enough people to get the message we don't take this kind of crap lightly, and he shows up too work. He holds a lot of power, but isn't going to use it. He's can delay, or miss, his daughters wedding for something this important. He would be back home the same day, and he's not going to suffer from PTSD.
His daughters wedding is important, but it's nothing when you put it into context of what others sacrifice for our country. They would love to have it as easy as Daines, who won't even go to the trouble to cast a vote in defense of the country.