My mom told me the end of her spine hurts when she moves and she can't squat. What does that mean?

Yesterday after swimming, my mom slipped and fell on her butt, when she stood up she told me it hurt just a little (I doubt it) then after she got back home, she told me the end of her spine hurts (the end near the butt I don't know whatever) when she sits and she can't squat properly cos it hurt a lot. I'm not an expert in things like this and when I tried to google it, the results are not what I expected. Does anyone know what it mean and what to do? I told her to go to she hospital but she doesn't listen to me :/ What should I do? What it it gets worse?
Please help! Your opinions are truly appreciated.
p. s. my mom is in her early fourties if you want to know.
My mom told me the end of her spine hurts when she moves and she can't squat. What does that mean?
Post Opinion