My husband tried to claim my adult some as a dependent bc he lives with us, and we pretty much support him. After going through the steps, Turbo Tax stated that he could not claim my son as a dependent. No problem. He finished the return and submitted it. My son later tried to file his return and it was rejected. Apparently, even though Turbo Tax would not let us claim him, our return reflects that we did. My husband is filing an amended return to remove my son so that he can file his own return. However, the deadline for my son to file that return is in 5 days. Should my son file for an extension? How can he avoid a penalty? This wasn't his mistake.