Don't understand why my fiance would want to buy a luxury suv for his mother

My Fiance and I when we get marry due to his job will be moving to LOndon. He has suggested that when we move back to the states we buy a used but for his mother he wants to get her a luxury suv such as a volvo or lexus. I said and why is that he says because she is old (she is 61 i don't think that is old at all) and she needs safety features. I said to him if anyone needs safety features will be us when have kids. I feel that once again everything is about his mom. Why does she need a luxury suv to go to church, some errands and come back home.