Calcified proximal total oclusion in LAD

My father (66yrs) is non diabetic and  has stable angina symptoms. He is having mild chest discomfort in the right side for a few minutes while starting walking, and after a few minutes of walking, chest discomfort is going away and can walk without any chest discomfort for a longer time. Recently he had a CT angiogram and it shows below dominant blockages. LAD : calcified proximal total occlusion, near retrograde filling from RCA Right coronary: Dominant vessel, proximal to mid 70 to 80 % lesion, distal 20 to 30% lesion. There was no heart attack history and heart is completely healthy from 2d echo and others reports. We don't  want to go for a bypass surgery, as he has stable angina. Is it possible to go for orbitral/laser atherectomy to fix these blockages. Please suggest..