Family issues

My sisters 3 year old is the same age as my son, we live in the same house at home (I’m a single mum with 2 kids so it’s impossible to rent as the prices are high af in NZ ect) she has 1 kid that she has 60% of the care and a partner. She also works full time and gets money from IRD weekly too (govt) she also tells the government that she has no partner so she gets daycare payed for... and gets $750 a week... do any of you see the problem here? She’s so greedy and her daughter is so naughty she his mum face and her mum rewarded her after doing something naughty.... my son doesn’t hit and scratch people’s faces. Even at daycare she scratched a BABYS face and the mother had to take it to the doctor 🥴 I’m a SAHM and I said how much I get... and she said “I work my ass off” LOL I look after 3 kids as well as a 4 month old that had a postnatal diagnosis of Down’s syndrome... I work my ass off!!!!!!!