The court will not typically credit the father's arrears because he had given her money for activities or paid other expenses. He is only entitled to credit if he makes direct cash payments to you or to the Domestic Relations Office. There are some exceptions. If he has paid uncovered medical expenses prior to your reaching the $250.00 deductible or if he has contributed to daycare expenses he may be entitled to a credit, but under the circumstances indicated in your question, there should not be any credit against the arrears.
My response is based solely on the limited information contained in the question. It is not meant to substitute your attorney's advice.
I agree with previous answer: credit is given only for direct payments to the Domestic Relations Office. Generally, direct payments to he child, however, would be treated as a gift, and NOT credited to arrears.