Drillbit Taylor (2008) on Netflix

Homeless veteran Bob 'Drillbit' Taylor manages to enjoy life anyhow and even saves some cash for his dream, an 'all-paid' move to Alaska, even if that may take many years. His dream comes within reach when clever nerd Wade, has fat friend Ryan 'T-dog' and cocky shrimp Jim, all new to high-school, are bullied so badly by emancipated Filkins and his buddies that they advertise for a bodyguard. Only Drillbit seems affordable and not crazy, so he's hired and drains their pocket-money and home content. He's clueless how to protect them but gives them (bogus) self-defense classes.