Child support

My boyfriend goes next month to determine child support for his oldest daughter. Right now he has no bills in his name, but he pays the electric and pays my sister to babysit our daughter. If I write him a paper saying this will that count as a bill? Also will they consider our daughter when determining how much child support they give his first BM? We get his oldest at minimum 2 days a week but lately it’s been about 4 days a week. I was planning on going back to being a stay at home mom, but with child support I’m scared they will take to much out. He makes 1,400 a month. He makes $700 every two weeks. We’re in Columbiana county Ohio