Ok ... you believe your teen when they say they didn't fill in a W-4 at work and they are getting a paycheck ? Check with the employer if you must or simply look at paycheck stub to see if taxes are being withheld.
Next, if they receive SS benefits due to a death you do not need to alert SS that they are working HOWEVER the SS benefits are included on the child's tax return because they are the child's benefits not yours even if you are the adult payee for the child. Now unless the child earns more than $ 12,200 for the year none of the SS benefits will be taxable.
