I had a friend like that. I lost down to a size 5 trying to win his approval. It's really sick. He ended up marrying someone who was probably 5 foot tall and was maybe 100 pounds soaking wet. So thin
she couldn't conceive. Years later she had to have a hysterectomy and is now spreading, so she starves herself and drinks a lot of her meals
to deal being with him. Sure glad I dodged that bullet and he married someone else. He runs obsessively to keep his body a certain size.