No, you're not liable for another person's taxes unless you file a joint return OR he's given you significant gifts (over $1,000 is about where "significant" starts). If he's given you a car, for example, there is a good chance that the IRS will come after you for the value of the car (the value when he gave it to you, not the current value).
Answered on May 25th, 2015 at 4:35 AM