If your friend lets you drive his car and then you get into an accident and his insurance does not cover that do you have to pay for the repairs?

Assuming that you were At Fault in the accident: you broke it, you bought it. Do you have full coverage on a car that you own? It might cover the damage if you were only using his car temporarily while yours was unavailable. If another driver was at fault, your friend should be trying to collect from him or his insurance.