OK, in a RX "IF" stands for "Intermediate Frequency". Some RX use single IF's and others use dual IF's. Hence the terms single and dual conversion you hear about receivers. The "IF" section basically (but not exactly) changes the frequency inside the RX by mixing signals together. Don't worry about the technicalities, they're not important to most. Can an "IF" burn up? I've worked in electronics and/or a/c avionics for 40+ years now and have never heard of such a thing. I have seen "IF" circuitry fail to operate though.
As for a battery pack shorting out and causing a temp surge causing this to happen? The gentleman has a big bag of "Hooey" there. Can't happen. Even if there was somehow a current surge it wouldn't reach the IF sections.
Don't take your Receivers/Transmitters to the "good 'ol boy" down the street for repair if you like your stuff to work.
Sorry, I'm in my "be blunt" mood tonight.