How is this site ranked?

Hey guys, so I was checking out my uncle's two sites for his businesses and noticed something strange. One is a PR3 and one is a PR4, but their traffic and backlink profile's are complete garbage. Literally the PR4 has 800 backlinks total according to ahrefs. The site is missing keywords in META's and as far as I can see, there is no major SEO work done to either site. The ONLY thing that I can conclude from this is that because his sites are about 5-6 years old and actually contain legitimate content, Google ranked them quite nicely. I know many of you are going to say "no duh idiot that's how it's supposed to be", but let me ask a question first. By this site's logic, does a good site with a shitty link profile and SEO work will still rank in due time?

more than sure you missed something

Alexa traffic puts his site at 4.5m in rank. I know ahrefs can't tell the amount of backlinks actually indexed by google, but even then google usually is much less than ahrefs says. I don't know what I missed lol

aged domain with good contents ranks alone pretty well buddy!

Hmmm...

Try to check their inbound backlinks PageRank.