What Is The Life Expectancy In A Person With Pacemaker In Heart?

my mother is 81 years old and has alot of health issues she has been told to wear a cpap but she will not and she has a pacemaker because she has some blockage and one vessels is not working she went to the doctor and he didnt let me go in with her and she understood that only half her heart is working so now she is very upset and thinks how can she live with only half a heart please help me