Is there any way to get Medicare to pay for my Dad's chair van when he visits the doctor?

The rehab center my Dad is at says medicare will not pay for a chair van under any circumstances, they only cover travel by ambulance in an emergency. The van ride is $90 and right now he needs to use it because he is still unable to go by car. He needs two people to assist him getting in and out of his wheelchair and he cannot walk yet. I guess my Dad discontinued his supplemental health insurance back in Dec.and Medicare is all he has.

Medicare told my sister that she could try to petition for coverage of the chair van (no promises) but that means the rehab needs to do a lot of supporting paper work. A letter from the physician and multiple forms to be filled out. My sister got into a HUGE fight with the head nurse and physician because they told her it was a waste of time. They have never seen Medicare pay for this service. Do you think that is true?

I'm all for advocating for my parents rights but I think my sister is really going about it in a bad way and she is the one in charge. She really went ballistic when she the head nurse and physician said she was wasting her time and theirs, so needless to say things are a bit strained on that front.

To make matters worse this took place in front of my Dad and now he is paranoid that the facility is trying to cheat them. It's so bad he wants me to take the quilt home that I brought in because he is worried someone is going to steal it.

My sister also made a big issue over the fact that the window in my Dads room does not lock very well and anyone could break in if they wanted to. Now my Dad is worried about that too.

I said I was going to keep my mouth shut unless my sisters bully behavior started to affect my Dads welfare and now I'm worried that might be the case. So I guess I have two questions.

1. Does Medicare cover chair van rides to doctors appointments from rehab?

2. Should I say something to my sister? Keeping in mind that she does not handle even perceived criticism well at all and it could just turn her ire in my direction.