I'm filing for my son that died on 12-31-2016. He had only $30 at that time but owes over $600 in federal taxes. What do I need to do?

I am sorry for the passing of your son. 

You may file your son's final tax return, but you are not responsible for your son's tax debt.

See below for guidance.

http://moneyning.com/money-management/heirs-responsibilities-after-a-death/

http://finance.zacks.com/happens-federal-income-tax-debt-person-owes-dies-6209.html

https://turbotax.intuit.com/tax-tools/tax-tips/Family/Death-in-the-Family/INF12090.html