My father left knee was shaking some times while he in stand he may got some unbalence to stand'. he was not daibetic but has hypertence?

Go see your doctor: Well, go see his doctor (but you get the idea). He (your dad) needs to be evaluated. Hypertension increases risk for stroke which may cause imbalance & inability to stand/walk. So make sure blood pressure under optimal control. I don't how things work in india but here in the states, we ask physical therapist to evaluate gait, strength, flexibility, fall risk, etc.