I wouldn't recomend jumping from the frying pan into the fire just because someone else did. When one team member becomes uncomfortable with proceeding, the team stops. If you feel that you should end the dive then that is what you should do and that is what your buddy should do. If your buddy has left you this is all the more reason to end the dive. You will not be helping anyone by placing yourself in a situation where you are not comfortable. If I were in your place I would have 1, ended the dive 2, Had a serious chat with the buddy who left me 3, consider a new buddy