Is it okay?

Anisha • || 20 • Island Queen • In love & Taken by Anthony J Boos • mommy to 1 fur baby & 2 angel babies but still going strong 💪🏽 • Never lose hope! • TTC #1 • Baby dust to you all! ||

So this is a question because I'm concerned. My sister in law has a 2 month old and she just allows her to cry. Now for me that means baby needs something and I'm always quick to rescue her but she's always like "she's fine, let her cry" I've heard that it's okay to let your baby cry when they're like 6mo+ but your new born? You're basically ignoring their needs correct? She always just leaves both her girls in their soiled diapers and I'm the one that needs to change them and when I do then she says "you didn't have to do that" but if I don't change them she literally lets them stay in their dirty diapers all day long. Saying diapers are too expensive (which I know they are) but when your baby's diaper is full you change them. Her new born has diaper rashes on her bum now because she lays in her own shit. I just feel like she's neglecting her kids a little. Her 1 year old is even starting to call me mama now because I take care of her more than her own mother does... what do you ladies think? Comments?