X Games snowmobiler Caleb Moore is in critical condition in a Grand Junction, Colorado hospital following surgery to stop bleeding around his heart after a crash last week. Moore's family has said that the prognosis is grim and aren't hopeful about his survival. Moore was performing a flip during the Snowmobile Freestyle event at the X Games in Aspen, Colorado when he underrotated and his skis hit the top of the jump sending him over the handlebars. Moore's snowmobile also struck him in the head as they both came tumbling down. Moore was able to walk off with some assistance and was originally diagnosed with just a concussion. However, Moore developed bleeding around his heart and was flown to Grand Junction, Colorado where he underwent heart surgery. His family also said that Moore had a complication with his brain. "Caleb is not doing good at all." Caleb's grandfather Charles Moore told The Denver Post. "The prognosis is not good at all. It's almost certain he's not going to make it." A Moore family spokeswoman issued a statement on Tuesday thanking fans, friends, and family for all the well wishes and prayers during Caleb's difficult time. The family declined further comment. Caleb's younger brother, Colten, injured himself in a crash on Sunday. Colten Moore suffered a separated pelvis in his crash during the Snowmobile Freestyle event. If you want to make a donation to help the Moore family pay for Caleb's rising medical bills, please visit the family's Give Forward page.