Disabled grandpa gets fucked by a redheaded teenager who wants his milk

It was a granddaughter totally devoted to her grandfather, this was an old man who could no longer fulfill most of his functions, the poor man was in a wheelchair, so she was in charge of most of his needs, that day they were having breakfast together, when one of her best friends arrived, she was a beautiful redhead teenager. That was noticed by her grandfather who kept looking at her, then he had an idea, he took her friend aside and asked her for the strangest favor, he wanted her to help her grandfather enjoy sex just for a while.