Is this mental weird?

My younger SISTER likes to pee in bottles. She has these pee bottles alllllll over her room. Sometimes she even pees in ziplock bags!!! Her room smells like death obviously because sometimes she misses. My mom wants to take her somewhere and get checked out but she says it’s just to “check her hydration levels”. Is this weird to the point where she needs a doctor??

Side note because I know people will say it , This is NOT a joke i wish I was joking lmao