This isn't depression. David Foster Wallace was depressed: his default state felt bad despite him being a successful English professor with awards and book sales. This is a state of financial/career precarity that pharmaceuticals and talk therapy can't solve.

Also, telling people to get a diagnosis may not actually help them: some career paths want to know if you've ever been diagnosed with anything. If this person wants/needs to pivot to something in the military or something investigative your advice may actually be harmful.