Good lord! Hell with the vehicle!! This is good news at the end of it all with your loved one being ok. Poor fella, I can relate 100%.My son was having an allergic reaction, I forgot his epi pen, and had pulled into the ER parking lot on the way home. Gave him Benadryl as we have a few times which usually works, it worked, so we headed out, but still needed to get him home to settle down, and then boom, it cut out dead soon as I got to hospital exit.
As far as the vehicle, all older and modern vehicle batteries start going dead as soon as the key is shut off. The parasitic draws and electronics on the modern vehicles taxes the batteries. I see thread after thread across various forums blaming either cheap batteries or the auto shutoff-start /stop.
I have given my solution here in the forum threads numerous times to prevent what happened to you. For years I have had pigtails and battery tenders hooked up to my batteries whenever my vehicles set more than a day. I typically get 5-8 years or more out of a battery.
The Passport (as do all modern vehicles) uses a crazy amount of energy through the battery. The electronics and components such as the electric steering tax the charging system.
Every time I rotate my Trailsport into the garage and plug it in it's under 75% (according to the NOCO indicator). When it sets in the driveway for more than 24hrs not hooked up the start stop does not even work. For short trips around town I get the error msg on dash cluster.
When I pull it out of the garage after battery is topped off the auto shut off-start/stop works immediately and seamlessly. Most of the time I shut it off for short trips around town. So far, knock on wood, I have not forgotten to shut it off. I have a meticulous routine each and every time I get behind the wheel or handlebar of any vehicle. It takes less than a minute to be ready and pull out of driveway.
I do understand that in emergency situations you expect your vehicle to be at the ready. Do yourself a favor and get into the habit of hooking it up to a maintainer.