Deductions & credits

I'm asking for my sister.  They rent a home that our parents own and each of their families or friends help them financially.  My sister's Husband doesn't have a taxed income and my sister was out of work due to her complicated pregnancy and then couldn't get back to work because of child care.  She is wanting to start working before the end of the year so that she has an income of some sort but she didn't know if it would make a difference.  She was looking to know if she would still receive the credits for their two children if she doesn't make much money within the next month and a half.