Dead Man Walking

Kreacher goes back to save his master, and Regulus survives but his near-death-by-Inferi puts him into a coma for the next sixteen years. When he wakes, well, the world is not so different. Voldemort is still at large, and the Ministry is still inept. His brother's got a godson now though, so it's only natural for Regulus to keep an eye on young Harry as well.