Need to vent , need opinions and advice or feedback

Okay so me and my boyfriend been dating almost 2 years , & living together.. in the beginning of the relationship he said his children’s mother had no where to go basically no job so , we agreed to get them full time while she gets herself together.. 3 months pass she come back , & she just grabs them back , ( she got them on a weekend , & never bought them back ) ... but she had no where to go so they needed up a shelter .. so okay , she gets a place income tax time , gets evicted few months later and now she’s place to place. He told her to give them back to us full time , until she gets on her feet . . No she’s no a drunk and she don’t do drugs. MEN are her downfall... so his mom calls him today and saying the kids are sleeping at a hotel , and she’s gonna get a place to stay in one tax again which is like next month she can get refund. He says he has to speak with her about this situation , for the 5th time. shes 33 years old .. I don’t understand her , she’s bitches at us and talks mad shit like she has her life together. Clearly she needs help , and we are trynna help & get the kids. Ion know I just needed to talk. And yes everyone keeps telling him to get custody , long story... he’s trying though.. And another thing , she tells her kids not to talk to me!! Even though she left them with me 3 months , I feed them , I’m there for them & etc. they told me she said it .