loose wires

It looks to me like plastic suround was molded to the metal spade. My guess is those two spades were then crimped and to the wires and finally snapped into the big plastic housing. I don't think they were meant to be removed. If you used an epoxy, that might hold it. If you go that route my suggestion is use the just enough to hold it in place and seal the cavity. My thinking here is that if it get hot, the more filler, the more difficult it will be for the heat to transfer away.

You may already know this, but both of those big wires are always electricly hot, even when the key off. Disconnect the battery when working on them with metal tools (or if wearing something like a wedding ring)