My money is on number 3. I bet the RT22 has an RX tone set. Seems like we are seeing more and more of these FRS radios being shipped out with tones already set.
It could be that from the kitchen you are actually getting the signal through under the thick part of the trees. There was another guy here a few months ago that was dealing with that same issue.
Like @N6CST I have a Tundra and went straight to the battery. The grommets on each side of the truck have a nipple top and bottom. I used the bottom nipple on the driver's side. Top was already used. The install was very easy. Running the wire from the cab side made it easier to see where to fish the wires.
Some did, some did not. Some had backup power that lasted long enough for mains to come back online, some never lost mains. Some lost antennas, some did not. I had one ham repeater and one GMRS repeater I could still use. Also had some ham friends just close enough for simplex.
I fight this same battle and it can be quiet frustrating. Especially since we just recently went through a hurricane and two-way radios were all that worked.
It's a good idea to use your radio regularly to stay in practice. In an emergency stress will be high and the last thing you want is to be fumbling with the radio or worse, a dead battery.
With that "kit" he will not need another adapter for a mobile. All he will have to do is remove the SMA adapter being used for the HT. The cable already has a PL-259 which is why it comes with the SMA adapter for HT in the first place.