7 year old nephew STILL hasn't started school. Concerned Aunt. Update

I wrote a post awhile back about my 7 year old nephew finally starting school. Well he'll be turning 7 Nov 12th. He's never been to school ever. He's only been to daycare. They have a younger brother who isn't biologically ours but we call him our bonus nephew and he'll be 6 in January and he still hasn't been in school yet either. I call my oldest nephew to check in on all of the kids and see how they're doing, how school is going with him and his sister and I always ask if the two youngest have starting school and it used to be his mom said Monday and now it's just no they haven't.

Wtf is she waiting on? I just don't understand. I've made posts in the past about her carelessness when it comes to the kids. I know she's very self absorbed and doesn't really care about the kids but come on. She complains the kids get on her nerves well send them to school for 7-8 hours a day. It's just frustrating because my nephew doesn't really know how to spell, count, etc. I think he has something wrong mentally and he has behavioral issues.

Is there something I can do? Is there a way to report it? They literally sit at home all day watching TV, or on the phone playing games. We try to be involved as much as possible for the sake of the kids but when it comes to her parenting she takes care of her kids and we need to mind our business, according to her fb page🙄. I did text my brother (their father) whose is in Texas about it but he can't really do anything so far away or can he? This is what his reply was. It's just frustrating because my nephew really wants to go to school. He really needs to socialize instead of being at home all day. When I talk to him he gets really excited and talks about what kind of bookbag he wants.

Edit: So after a couple more text exchanges my brother called me immediately and we talked a good hour about what we can do. His text was stating he didn't know his son was having surgery and didn't know what else to do besides call the school. We talked about how she admits that she is keeping the kids from him on purpose and trying to stop him from having a relationship with the kids and a bunch of other things going on. I'm not making excuses for my brother because he has been a shit dad but his kid's mother has been trying to push him out of their lives since they broke up he's trying to do better now especially since moving to Texas and getting his own place, working, car etc. He does care about the kids but he just feels useless because he's down there and doesn't know what else he can do but call the school constantly and report it and they'll do something but I feel like there's so much more that we can do than call the school. So should I just call cps because I want more to be done then just calling the school? I've been in these kids lives since day one and seen how both of the parents are and let me tell you they had no business making babies especially after only knowing each other for 2 months before planning my nephew.

Update: I talked more with my brother today. I guess my nephew is having surgery Monday instead of next month. Since it's coming up quick he wants to see if she puts him in school after he recovers. He's having surgery on his hernia. I told him I will be reporting it to cps if she doesn't. I'm giving her a week maybe even less after the surgery. He's scared that if I contact cps that the kids will be given to the state because they're in her care. Well technically her mom takes care of them while she does her thing and she recently got evicted before school started and is living with her mom🙄.