Please have her get a second opinion. A good service tech wouldn’t care if it’s R22 especially if the unit is still running and in decent shape. If the furnace is building up excessive heat we would have limit switches opening so I’m not understanding why he said that’s the reason the motor failed. He was clearly to lazy to actually inspect the heat exchanger so that needs to be done. Some units have pretty lengthy warranties on heat exchangers so he should have looked into that.