There are some requirements I would look for:
1. Do they have automated tests?
2. Do they enforce code reviews?
3. Do they use some type of continuos integration system?
4. Do they use source control - preferable Git?
5. For the server side, do they use a statically type language - Java, C#, or even NodeJS/TypeScript
6. Do they have organized training sessions like lunch and learns?
I'm at a point in my career now where I'm pretty confident in what I know and I'm the only architect at my company. I ask for advice a lot from some of my former more experienced coworkers on a private Slack channel that we still use.
I totally get where you are coming from because I began to feel I wasn't learning anything new and just repeating the same processes. So I left after 3 1/2 years.
Since then every job I've had I try to work for people I can learn from and grow.
Having people who can mentor or just being around smart people and seeing how they work and implement processes can be really helpful.
If only that were true. There is a difference between having 7 years of experience and 1 year of experience 7 times. If he hasn't had a mentor and been in a bubble, it's possible that his skill set is not as high as it "should be" based on the number of years he's been working.
I found myself in a similar situation around 2008. I started programming in 1986 when I was 12 in AppleSoft Basic and assembly, went to college, got a degree in CS in 1996 and spent the first 12 years of my career being a solid C++ "programmer", who dabbled in other languages.
During those 12 years, I was also the only programmer at the company without a mentor. I could write clean code, bit twiddle with the best of them, but hadn't been exposed to sound engineering practices.
In 2008, at the age of 34, I humbled myself, got a job as what I would consider a junior "software engineer" (making about the same thing as I was already making) and spent the next 8 years, learning from others, studying, and job hopping my way between 4 jobs and becoming what I consider a pretty good architect.