Question about Type 2

My father was recently advised by his doctor that his blood sugar was high. His A1C was 6.1, up from 5.9 6months before. Even though I’ve been type 1 for almost 30 years, I have no idea about the pros and cons of different type2 medicines. Do they all work the same? Are there side effects? My dad is in his early 70’s and eats a healthy diet and exercises. He had a heart attack 15 years ago, but hasn’t had any problems since. What would you suggest?