Help for grandmas mortage

This is sad story about my grandmother and grandfather...They live with 500 dollars a month and they have mortage on their house which they cant pay anymore because grandma is very sick and they spend almost half of their money on medications...I m trying to help as much as I can but they are already late with 4 rates.Please help them to get back on their feet.I am 20 years old and I am working 16 hours a day to help them to live like nnormal people...it would change my family's life for ever to help them pay back this late rates.Thank you