I Have Just Received A Back Child Support Check

I have just received a back child support check in my deceased wife's name for my step son who is now 19 from the state. she died 6 months ago and i was married to my wife for 10 years in which i supported our family. i was wondering legally if i am able to deposit this back owed child support check in an account we still have open jointly. i have supported this child since he was 4. these checks have come randomly over our married years and i feel someone is entitled to this money.