Every time the compressor tries to come on it pops the breaker. A friend who has worked in AC says its because the compressor is going bad. Is this true?
He could very well be right. When bearings inside the compressor start to bind up due to age, they increase the running amps. Once that amperage exceeds the breaker size for a period on time, the breaker will trip. Eventually, your run amps will equal your locked rotor amps which can be three times the normal running amps.
Things to check first would be all the connections to make sure none of the wires burned and are shorting out. Also check the contactor for failed parts that might be shorting out. Check your disconnect switch for any burn marks.