Momma's being momma's

I can not understand why a lot parents, especially mommas don't have more instinct than they do. ( this is personal, not knocking anyone) I have a niece that has 2 beautiful boys and I wish she would grow up and be a momma. She is more worried about this man that don't give anything to their relationship and her drugs. Maw maw does most of the care for the boys and I help maw maw out by babysitting. Sam has got her a job (again), but when she gets off, she is off till way after bed time. And you can't find her on the week ends. I'm glad she don't take them off with her, but this will come back and bite her one day. I took the youngest to the health Department this morning only to find out that he was way behind on his shots. He just turned 1 in September and his last shots were done March of this year. So, the poor fellow had to have 6 shots and will get 6 more in 6 months to get get him caught up. She had been telling maw maw and me that he had all his shots. I love her don't get me wrong, but she has drained the life out of maw maw and me.
She isn't the only one I know that has babies and don't take care of them! AAARRRHHH! I just wanna shake these women and ask them what the "HELL" is their problem. I don't mind helping and babysitting, but these little darlings need their momma. In my point of view, if she or others not wanting to be a momma need to leave the scene and quit playing games with these babies.
I protected Sam one more time yesterday, but the Health Department still made a check mark. I told maw maw this and she asked me why didn't I tell them the truth, that she was lazy and unfit. I just told her I didn't feel it was my place. I wanted to, but them maw maw would have held it over my head. If & when she has had enough of Sam's grap I feel she will put a end to it. But Sam is my niece by marriage and maw maw raised her. I know she probably wishes Sam would straighten her tail up or leave or someone would report her. One of the options would give us all a lot of relief, but I personally don't need maw maw mad at me for something that she can do her self, but if everyone keeps looking away the Health Department will do something.