yeah bb there are some older converters that had that type of system internally, after some thinking the model J's heat exchanger is isolated, basically a straight through path. But it did strike me funny he says he has coolant in the vapor line and mixer. Where was it comming from then? Thats why i was thinking this, there could still be an issue in the converter like a cracked exchanger or something.
So with that said replacing the converter is still the right course of action to take imo.
Since he seems according to that picture to have the cobra converter since there is no primer button on it he can look on the cover and there are numbers specifying pressures he can use to get the correct one. OR he can just remove it and take it to the parts store and match it up.