The Lazarus Child (2005)

A 12-year-old boy babysitting his younger sister, turns his back for a moment, during which she and a friend get hit by a bus crossing the street. Deep in a coma, the sister's condition is dire and further frays the estranged parents relationship and plunges the brother into deep depression. The only hope is a radical form of treatment devised by an eccentric researcher. In the researcher's treatment, a person enters the comatose person's mind and tries to communicate with them and bring them back to consciousness. With time running out the guilt-racked brother volunteers for the job.