Is that neglect

My sis in law baby is 6 months, she refuses to take baby to any appointments. She even canceled her and the baby insurance because she didn’t want to pay for it anymore. She also gives baby a bottle only at bed time, and solids rest of the day. She says it’s cheaper that way and saves milk. I am in no way bashing her as a mother I am honestly just concerned for the child. I know everyone parents different and have the right to do as they please with they child. Maybe I think to much, but I just worry is the child getting enough nutrients. I worry because some days will be crying like it’s hungry and she will just say it’s ok will cry itself to sleep. Some days it break my hurt. I have two kids of my own and I know hungry cries. Now i know all babies cry different and maybe her kid was just being fussy. I’m I worried about nothing or should I try talk to her or just mind my business becaue it’s not my child?