Long but I need help pls

Concerned bonus momma here.

We get baby every weekend, if not more. We noticed baby sometimes comes home in the same clothes we sent her in.

At first, we figured she was just sending our clothes back. But we noticed she would have the same underwear as well.

Baby is a toddler, so accidents happen. Well, mom had called to say she had a #2 accident. She comes to us, 2 days later with underwear that have said accident in them.

We even asked baby, “how often does mommy bathe you?” And she always responds, “she doesn’t.” We asked if we are the only ones who bathe her, and she responds with yes, and sometimes auntie who baby sits every once in a while, when mom works late.

Even in pictures and videos she sends to us, she wears the same clothes throughout the week, or the first few days after the weekend.

We are writing these incidents down, but I was wondering if there is other ways we can tell if she’s bathing her? We tried asking, but she always says “of course i do, why wouldn’t I?” And gets offended.

We’re just concerned. Mom lives with many people, and baby voices how often mom leaves her in her room while adults have fun.

She lets her stay up all night, have candy instead of food. Mom doesn’t hardly cook/eat, meaning baby hardly eats.

We are relatively new to all of this, and I am not trying to say she is a bad mother or doesn’t care. We just want to make sure baby gets the care she needs when she isn’t here. Often she sends baby to grandparents (and doesn’t tell us) to go out. She usually goes out daily. No judgement, but we started asking her if we could get her instead to have more time.

Any suggestions? We want to know the best thing to do.