Is Alcohol Consumption Safe Post Aortic Valve Replacement?

My dad had aortic pig valve replacement and mital repair His meds are. Corig for heart a thyroid med, diuretic, potassium, Vitorin for cholesterol, baby aspirin, Allegra, lexapro. I feel he shouldn t drink alcohol. When he drinks it is anything and usually 2-5 drinks Isn t alcohol a really bad idea even if he consumed less?