My Dad Has Blockage Of 80 % Followed By 99% In RCA

my dad is at age of 67 and recently he had shoulder pains,so we went to hospital and checked.from cardiogram doctor tell us that he had mild heart attack . Doctor suggested that you must have to go for Angiography. from Angiography doctor tell us that he has Blockage of 80 % followed by 99% in RCA (right coronary artery ). then they attempted for angioplasty but was not successful, due to hardning of blockage, so he suggested for Bipass Surgery . so we take the advice from a hospital , thay see the angiography CD and suggested that as previous doctor attempted for angioplasty and was not succesful, there is no need of angioplasty and as it is in RCA we dont need to go for Bipass surgery also . Doctor gives some medicine and said it will be cure by medicine no need to take tension and ask to come after one month for checkup again. now 15 Days has been passed. But still my dad is having pains of Both ARMs and Sholders, he is taking some pain killers like Combiflam. Please please please suggest the Risk factor and proper guidline to follw i am very much warried about my dad.