you don't 'get a postdoc'. It's not a degree. It's a job you get that requires a PhD. It's a form a purgatory until you can get a real academic job.
The goal of a post doc is to continue to do research work where you're the first position on publications to pad your CV to the point where it looks impressive enough when you're out giving job talks for tenure track positions.
If you have a very strong PhD thesis, produced a lot of good work during your PhD and made enough connections, you can skip that step.
A postdoc is not a PhD but it can also be competitive in good places. Very hard to skip that step these days unless you're a superstar, even in CS. But it doesn't really matter. Are you trying to discredit him in some way? It's actually even more impressive he got to where he got without a degree from a top school. He needed to work harder than others.
The goal of a post doc is to continue to do research work where you're the first position on publications to pad your CV to the point where it looks impressive enough when you're out giving job talks for tenure track positions.
If you have a very strong PhD thesis, produced a lot of good work during your PhD and made enough connections, you can skip that step.