An ICD is a pacemaker that bites
I have a card that was issued by the manufacturer. I move it, my ID and a credit card to my pocket from my wallet before moving everything else from my pockets to my carry on. I also remove my belt ahead of time and put it into the carry on as well. I have never been asked by anyone to see manufacturer's card nor has having it changed the protocol one bit.
While I know the drill, I use the medical/family lane if available. I have occasionally had "conversations" with the moat dragon who wants me in the general lane. The rest of the prep into the bins is as usual.
While my device is not effected by a quick trip thru the WTMD, it is generally detected. The result of that was a thorough secondary and a lecture. The lecture was to tell me that it is less of a hassle to be manually scanned than to have to clear the alarm.
Just before the WTMD I get the attention of the screener. Most are surprised, some seem to be a little irritated. At this point I say, "I need to be manually scanned, please." If they hesitate, I point at my chest and say, "pacemaker." Except for a couple of times that was all that was necessary. I think that the other times it was a matter of noise or some other distraction, that they didn't understand what I was requesting. I have occasionally been told to just walk thru the WTMD. I have decided that this really isn't an option so I smile and say that I would rather not "end up on the floor flopping like a fish." This isn't really what happens but I have never had to go farther than this.
Most places I get put into the Plexiglass cage while a "male assist" is summoned. When they arrive, they generally collect my bins and carry on from the belt and take me aside. Occasionally they will reach for the wand but, usually they start with the pat down protocol.
The pat downs start with an explanation of what they are going to do. They are thorough but I have never felt any hint of retaliation. If they are conversational, I will chat. That is unusual.
Smaller airports are generally easier to negotiate than large ones. I have had less than stunning experiences at:
SAN: separated me from my belongings while waiting for the male assist. This was more of a configuration problem but not well handled. I had to be escorted down the concourse exit to get to the screening area.
LAX: Had to start from the beginning because they could only allow me in at the medical/family line. This was where the moat dragon insisted that I use the general line rather than where I had been sent. This in spite of the fact that my stuff was in a bin and that I was not coming from the main entrance.
PHL: Just a general not friendliness and an impression that I am an inconvenience to them.
Empire State Building: "WE HAVE A PACEMAKER HERE!" Thanks, I would have worn a sign if I wanted EVERYONE to know.
I have never had any TSO doing the pat down be anything but polite and professional.
My recommendation would be that your father accept that life is different now; not worse, just different. By being prepared; i.e. everything out of your pockets, belt and shoes off, it demonstrates that you know what you are doing and you avoid any "teaching moments." The goal is to get past security with the least amount of hassle so don't invite it. Compared to what he went thru getting the device in the first place, there is not much that the TSO can do that would trump it.
lynn