Clearly, there is a limit- your opponent has 1 month and 14 days remaining.
Each person has a different limit, depending on what level of membership they have- Free, Gold, Platinum or Diamond. Free members get a maximum of 30 days, but platinum and diamond get 90.
Resignation if your opponent is on vacation is the same as resignation normally. Since you are in a tournament, you will lose rating points regardless of how far into the game you are.
Nytik
I am currently in a tournament and one of my oppenents is currently "on vacation". My oppenent has 1 month and 14 days of vacation time left. Does this mean that I may have to wait for my opponent for 6 weeks to play our game? If so, if I decide to resign will I lose rating points?
Is there a limit on the amount of time someone can be "on vacation" for?