Absolutely NOT!

He is the one making you uncomfortable and it is not your fault, you didn't cause him to make those comments or gestures. The blame is on him. He is your grandfather and an authoritative figure, he's someone you love and also respect and are supposed to trust. If he takes advantage of that then it is no one's fault but his own.

I can understand how you feel 'stuck' in the current situation though. I've been there myself. Maybe making a plan of how things could change and what your plans will be when you are able to move about freely will help get you through this darker part?

I'm sorry you are in this situation. Please remember though - it is NOT your fault.