How does this sound?
I'm sorry but having to stay home with lice is the same as sick days which are paid as stated in the contract. Lice is something contagious and if it gets spread to the other kids he could end up getting it again after all the work you put into getting rid of it. Also there is one mom who is pregnant and wouldn't be able to treat her child. I have to make an appointment to get my head check which I will have to pay for.
I do understand where you are coming from but it would also be hard for me when I'm counting on my income to be able to pay bills too. If you are finding daycare fees to be a financial burden you could try applying to OneList, they offer subsidy for child care costs.