Halfway through the surgery, the nurse came out and spoke to my Grandma and my parents and told them everything was going well, they got the veins from his body and were continuing on (they took some veins from his leg and from his back to replace the clogged veins). After the surgery was over, the surgeon came out and told them everything went well, that they didn't have to stop his heart. The surgeon seemed really pleased and confident that all was well.
Mom said they were keeping him in ICU, with the breathing tube in place, through today or tomorrow (probably just to keep him still so his heart could heal). Last I heard, they were bringing him up from the anesthesia, but as everything went well, there is no reason to suspect anything else.
Thank you for your prayers and continued prayers for a quick and complete recovery. I'll continue to keep you updated.