70-80% BLOCK IN LAD

My dad who is 80 years old having 80% blockage in lad is now on medication what will happen to him or what are the chances that the bloackage will go reduce by medication? what are the chances that he will have an heart attack?
he had an attach which was acute 15 days back and angioplasty was done for one 95% bloacked RA .But LAD is kept on medication.

[ed34]

If he is comfortable on medication and has made the lifestyle changes necessary to lower the risk of progressing his heart disease, then the blockage may never increase in size. Many people are lucky enough to be in that situation. If the blockage does increase, then it should be gradual and his symptoms will increase, giving warning signs. What are his symptoms at the moment with medication?