Saying this all cautiously.. When Lightning Strikes, it's not just the obvious bolt touching down on the (usually tall) object at hand. There's a huge number of columbs of electrons dumped into the ground; these then flow through the ground, through the air, and
away as the charge is equalized. (Or depending upon the polarity of the strike, it may have been a huge number of electrons that got
removed from the local environs, in which case a whole buncha electrons move towards where the pile of electrons were removed.)
Either way, there are some serious ground currents of Large Magnitudes moving around; and Great Big Electric Fields associated with these movements.
Just so we're clear on this: This is not somebody running a brush or comb through dry hair and getting a "snap" or two in the process. Those kind of snaps are up in the 5 kV to 50 kV range. Lightning strikes themselves have E-fields up in the millions of volts per meter; the H fields, associated with the currents are in the millions of amps per meter.
Rise and fall times of the strike and the immediate aftermath are in sub-nanosecond rise and fall times, which is why one can hear lightning strikes on radios, sometimes miles away. We're talking
significant amounts of radio frequency energy; any wire in free space (like those ones on the power poles) near a strike are going to absorb all this stuff, which is why the house next door to the strike often loses all the electronics in the house, whee!
(If you haven't figured this out yet: Yes, I do do lightning surge testing, part time, for a living. Most of the stuff I work with is inside buildings and isn't subject to a direct strike. Instead, the iron members of the building take the strike; there's a big surge of current down the girder on its way to ground; and the electromagnetic fields coming off the girder cut through wires inside the building and can cause, literally, thousands of volts to appear on wires with No Direct Contact.
What I really love are the standards for those grey boxes on street corners. The interior of the box is covered with a certain grade of cheesecloth, the box sealed up, and then the box is hit with a "Test" lightning strike. The standard says, and I quote, "The Equipment Under Test shall not become a fire or fragmentation hazard."
I can safely report that there Reasons telecom stays up during lightning storms; those Reasons include extensive testing to standards. And those standards are written by PhD types who write Serious Papers on Exactly What It Looks Like When Lightning Strikes.
I don't know nearly as much about the City Power grid: But pretty much anything that plugs into a wall socket has designed-in lightning surge protection to a certain level, and that includes anything from a TV to a refrigerator to a cell phone charger wall wart. Now, a direct strike on the pole outside of one's house might
exceed those levels, but mundane (ha!) strikes from down the block will leave people's stuff mostly intact.)
The magnitude of the currents and voltages flying through the air have been known to cause Ball Lightning, self-sustaining balls of ionized plasma that have been known to melt their way through (!) glass windows. (I've even read some notes from wishful-thinking cold fusion types that these are actually powered by fusion.. don't think so, but the Why of ball lightning, far as I know, is still actively being researched.)
Now, having said all this, there is a sure-fire way to keep all the electromagnetic energy from a lightning strike from frying something, or someone: It's called a Faraday Cage. Build a six-sided box with fine conductive screen all around (or solid metal, if one prefers) and the electric fields
inside the box are Zero. Outside, anything you like: But inside, Zero. In Electromag Physics I personally watched a demo where a volunteer was placed in such a 8'x15'x15' box up on the stage; the Prof had this weird piece of machinery with an 8' rotating copper disk in it, a cable with thick insulation like you would not believe with a naked 4' long piece of metal on the end, he had thick, heavy gloves on, and approached the cage with the end. It threw, I kid you not, a steady five-foot arc onto the screen of the cage, while that disk whirled frantically. Our volunteer inside the box put his hands flat on the screen on the inside of where the arc was grounding itself and said the fateful words, "It tickles a bit." The rest of us in the Lecture Hall were just impressed.
Now, take ye old-timey 1950's car built from pig iron. It's got some windows, sure: But all that metal out there is a fair approximation of a Faraday Cage. It's not the "insulating tires" that makes it safe: If a lightning strike just blew through several thousand feet of insulating air, what makes one think that, after all that energy hits a car, it's not going to jump the six inches from the car to the ground? Currents are going to flow like mad on the
outside skin of the car, but not on the inside.. where the sensitive electronics (shielded, in metal boxes, I might note) and
people might be sitting. Inside, the E-field is zero. And
that's why the safest place to be in a lightning storm is inside a car.
Now, the difference between one of those pig-iron cars and a Tesla is that the Tesla has a glass roof. So, unless Tesla has made the glass electrically conductive (which they very well might have), sitting in a Tesla is probably more like sitting in a convertible with the top down. My 2018 M3 has one of those glass roofs on top that turn this pretty orange color when it gets wet, so that color may be due to something conductive. That might very well be the case; but I have no direct knowledge.
In any case: Get big enough E-fields and H-fields changing fast enough, rapidly enough, and one can get GHz-style electromagnetic radiation, and that
can go through the windows on a car. Wouldn't hurt people, but it would induce rapidly changing currents on interior wires. So one might get the OP's observed effects of the electronics going mildly crazy. What sounds more hopeful is that the car appears to have survived intact. And
that, I presume, is because in some industrial lot somewhere there's a lightning strike simulator that Tesla engineers put their new designs through. (I'll even put up a nickel as a bet that there's bunches of ANSI/SAE standards for lightning withstand.. hang on a sec, let me check.. Yep, here's
one, one simple Google search.)
Sometimes, engineering gets to be real fun. I've got this ESD gun at work. It's old, but looks like it's straight out of Star Wars, with a double pistol-grip, pointy tip, and everything. Point it at people sixty yards away and they duck. But the most it will do is a half-inch spark
.