Hi. My Father Just Had His Second Open Heart Surgery

Hi. My father just had his second open heart surgery last Friday to replace his mitral valve and was only able to fix on blockage. He came home from the hospital yesterday. When he is sleeping his breathing is very odd. I am taking care of him while my mother is working. I am not saying this will happen but I asked my mother if he stops breathing should I perform CPR? I'm just curious Because of his incision and he does have a pace maker as well. So my question is if that was to happen could i do CPR or what would u recommend???