Power of attorney?

ok so it all started about 3 months ago when my step father has bacterial meningitis and became paralyzed and put on a ventilator well, my mother had the financial part and his kids ages 23,20 had the medical well my step-father then changed his mind and gave his kids both...(they only wanted financial when they found out he was still getting payed) well long story short can his son come and take my moms new car on which she has already payed around 2 grand on but the title is in my step-fathers name?......also, HE IS NOT IN A COMA HE IS ABLE TO TALK AND PEOPLE CAN LIP READ.......its not just the car can she lose the house? its not just about this but she doesn't want to be left on her also does she still have more access to the bank account more that them?