Secondhand Lions (2003) on Netflix

13 year old Walter has had a hard life, with his no good floozy of a mother getting together with many equally despicable men. Before going on yet another husband-hunting trip, she drops him off at the house of his great-uncles Hub and Garth. They disappeared for quite a while in their youth, and are rumored to have acquired a great fortune, which Walter's mother hopes to get her hands on if he can ingratiate himself enough to the two cantankerous men. Though reluctant to put up with him at first, Hub and Garth grow to accept Walter, and even tell him fantastic stories of what they were up to while they went missing. When his mother returns, Walter must take charge of his own life, and decide what he's going to do with it.