Am I wrong?

My husband can't drive his car for 6 months because he recently had a seizure. My mom is staying with us. Mind you, I was raised in foster care from ages 10-18 when I aged out I was homeless. She didn't let me stay with her because she felt like "I was a stranger" since we hadn't seen each other in almost 8 years. We mended our relationship 3 years ago and she came to me for a place to stay. She said she was gonna pay rent but then would call into work every other day until she got fired. She's been barely looking for another job. So I thought I fair deal would be she drives my husband around for rent since she has a license. It would be in our car. She doesn't want to because she says that interferes with her day even though she just sits around the house all day. I told her that would be her rent and she said "I'm your mom. You shouldn't be charging me anyway". She agreed to do it but has an attitude. Am I wrong?