Shabbat

Question

My grandfather is unable to walk to shul. He has two questions. 1. Can he hire one of the teenagers from the shul to push him there and back -- the boy would obviously be paid for work he did on Shabbat, not for any "preparation". 2. If he can't find someone to push him, is it permissible to hire a non-Jew to drive him to shul on Shabbat. The non-Jew would open the door to the car. Since at the most he is violating an issur de-rabanan and attending shul probably qualifies as a mitzvah, I thought perhaps we could say that this is a shevut bimkom mitzvah which is permissible. Also, I should point out that it is very painful for him to remain at home on Shabbat. Without attending shul, it doesn't feel like Shabbat.