I've owned many cars that have sat for months in a dehumidified garage without ill effects... However, I'd say a couple of things.
Roll the tyres onto carpet, sitting unmoved on cold concrete can create flat spots on the tyres. Not a massive problem, as they'll 'drive out' when you use it. But ideally someone could roll the car backwards or forwards by a foot every few weeks.
New cars don't mind being undriven too much - engines over 10,000 miles need running every 10 days or so.
Can you put some mouse poison along the walls of the garage?
Don't leave the handbrake on and ensure the front discs are bone dry before storeage.
