car stalling after 3 years of parking outside

We are trying to buy a 2012 Acura TL with 70k miles in Houston, Texas from a friend's friend who left the country three years ago. According to the friend who parks the car outside his apartment, the car ran fine for about 2.5 years during which he would start the car once a month and let it idle for 30 minutes. But he neglected it for the last 6 months until we asked him over a video call to start it for us.

First of all, the battery was dead. He jumpstarted it with one of those small Li-ion battery bank. But the car only ran for 2-3 seconds. After a couple of times he could not even start it. car cranked fine though. We found that the gas tank was empty. So we dropshipped him a two-gallon gas container to get two gallon of gas and put it in with a 1/4 bottle of Iso-HEET water remover/injector cleaner. Then we tried starting it again. But this time the car would start for like 1 second and stall.

I suspect this is most likely a fuel problem but want to be prepared for other possibilities. We are going to Houston this Saturday to see if we can get this car started and take it to a mechanic for a presales checkup before we commit to the purchase. It's a 3.5 hour drive so we want to be well prepared to troubleshoot it.

I plan on borrowing a fuel pressure gauge to check fuel pressure, and will check for broken air intake hoses and vacuum hoses, sparks, and corroded electrical connections. But I am not experienced in no start/ no idling situations.

Are there anything in particular about this model and any other common issues of sitting in a hot and humid coastal climate with virtually no usage for three years that might lead to this idle stalling issue?

I would really appreciate it if someone can help prepare me for this trip.

Daniel