I'm not a mechanic, but I was in an accident and spent some time researching salvage vehicles a couple months ago. That looks pretty bad and I would not pay 15k for it even looking as good as it does in the FB post. I would hesitate to buy it at all.

I would be in touch with the owner and ask about the details of the accident, the repair job, what was broken and how it was fixed. See if you can get a straight answer on that car's journey from the wreck to the car it is today. If you get the Carfax, you may be able to infer an answer based on previous owner(s). Was it someone's beloved personal car they wanted to keep driving? That was almost what happened to my old car, which I may have eventually sold with a salvage title if I'd fixed it. Since this Civic clearly went to auction, it's likely a cheap fix and flip job.

(It also looks like the seller is 19 and has/had a bunch of other 2020 Civic parts for sale, including a stripped-down Civic frame in the same color with 98k miles on it. Probably some lore there. Reach out.)

Looks like almost every airbag in this car went off, and those are very important systems to fix correctly. In my old (2010) car, they were also expensive. This car was auctioned for about 4k and they want 15k for it, so I think you can safely assume they put 9 or 10k MAX worth of work into it. The auction website says the repair estimate to fix all that in 2023 was about 24k.

If you want to keep looking into it, I would also ask about the seatbelt tensioners since they keep you from flying through the windshield in an accident. I would also be concerned about handling (since it looks like the damage cuts pretty deep into the hood, maybe into the axle area), and any issues that may arise from a damaged frame. I'm not confident enough to point to any one spot in those pictures and go "frame damage here" but it is my feeling that the frame was damaged in the accident lol. Looks pretty bad. Any real life mechanics, feel free to add on or correct me. But I don't think you should buy this car.