TIFU by opening a video after a notification on my phone popped up

My 20 year old son, Sage, was killed on August 26 of this year. While we are from Seattle, he was off at college in Prescott AZ. He'd joined the AFROTC, and they often did long, brutal hikes, and would generally party to celebrate after. That night, like so many before, a bunch of the kids piled into a jeep and were doing donuts in the empty lot next to the party house. Sage, ever the adrenaline junkie, was hanging out the window. There were a couple of his friends in the car who wanted to do the same, but since Sage outranked them, he told them no, it was too dangerous. That asshole knew it was dangerous but did it anyway.

The jeep rolled, and since he was hanging out of the window, it rolled on top of him. He was awake and alert for twenty minutes after, but they weren't able to get him to the life flight in time.

We chose a funeral home up here - he told me composting would be cool while we were having a conversation about what to do with bodies post-death... a conversation that occurred because 10 days before he was killed, his grandmother, my mom, had died. Hers was not unexpected, but it did lead to the conversation. A couple of weeks ago, the place notified me that his final effects had arrived and I went and picked them up, the second hardest day of my life (the first being the day we were notified). It wasn't much, just his phone and wallet and contents of the wallet.

I got home, plugged in his phone and went about my day. Now, ever since middle school, I've had his gmail account on my phone, though by 8th grade I started asking him if he wanted me to take it off. He always said no, just leave it in case he needed a backup. I respected his privacy, never went through anything without asking, ignoring the popup notifications of his photo activity.

Well, this time there was a popup tht said a new video was ready to be viewed. I didn't look at the account it was from, I just opened it, and for the first ten seconds I didn't really undertand what I was looking at, not until the scene started to rotate, then I realized he had been holding his phone out the window with him and caught the last few seconds on video. I stopped watching after I saw the initial tilt. I can't bear to look at the last 18 seconds. I'm also 100% sure that others at the arty were filming - 18- 22 year olds? of course they were.

But it sent me into a panic attack and even deeper grief for a few days. I don't want to delete it because it's the last thing I have of him.

TL;DR: Opened a video on my phone that showed the accident causing my son's death.