Daily game
It is called vacation abuse:
https://support.chess.com/en/articles/8584203-what-is-stalling
https://support.chess.com/en/articles/8609526-what-is-vacation-abuse
You can certainly report it.
It is really up to you. I would premove the checkmate in conditional moves, report him and just move on.
https://support.chess.com/en/articles/8583792-how-do-i-make-conditional-moves
Just resign and move on. It's only online chess between two people who are not even using their real names. It means nothing.
I'm new, but can't you just start up a different game and wait "vacation person" out? Maybe there's something I'm not seeing or am unaware of, but why the urgency beyond your (understandable) annoyance and wanting the W? It's certainly poor form on their part. I assume they automatically lose after some period of inactivity or not making any sort of move? But even if they are allowed to remain on vacation indefinitely why not just set the game off to the side and play someone else until they make a move? Again, I'm fairly new and probably don't understand all the rules and nuances yet. Feel free to roast me if I'm clueless.