My friend has been told he can only take paid FMLA if he has a child. His mother is very ill and needs round the clock care. How is this legal?

If I’m in the wrong subreddit please let me know where to go. ——— . Friend works for DoorDash (work from home, not a driver), and his mother is very ill and needs care. They told him he can only take paid FMLA if he has a kid. How is this legal? Is this even legal? He lives in Arizona. Trying to help him anyway I can.