Ah. sorry for not being specific. They left an ES330 and RX300 in the garage when they went on a trip (1.5 months). When they got back, both cars were completely dead. I believe the alarm system was disarmed (i.e. doors unlocked) when he popped the hood to access the battery. He then disconnected the battery and charged it for a day.
The moment he connects the battery, the horn blares. I asked if the lights were flashing, he said the parking lights were on. Not being fortunate enough to own a Lexus (yet), I do not know what the security system looks like when it is going off. He then tried the various things (while I was on the phone hearing the blaring).
Oddly, the ES330 did not have an issue having its battery disconnected and reconnected.
Anyway, if someone knows how to get them back on the road, I'd appreciate it. My dad is 81 and the closest Lexus dealer is 40 miles away so if we could solve this, it would be great.
Thanks.