Well Land,
The isolator should have maintained the separation of the chassis (engine) and coach (house) batteries, but I guess it did not. Even if the inverter was installed by Born Free, that does not mean it was done right. But as for dead, I do not know of an electric refrigerator that will not do harm to any normal house bank in two days.
The Engel coolers that I have known still have a battery drain that is a lot like leaving the parking lights on. Not many vehicles can do that for two days.
I suggest that:
You determine that the Freedom 10 I connected to the house bank.
You test the isolator to determine if it is functioning properly.
If the isolator is a BIRD or CDsolenoid, the device can stick or the contacts weld and then you have your case. In the boat business that the depression killed, I used to replace more than a few of the contactor kind isolators in any season.
Matt