You have just described the poster boy for self publishing.
As long as he prices his books over $2.99, Amazon will give him 70% of the price, so if he sells 30,000 books at $4.99 (approximately what novel length fiction sells for if it's not from a major publisher) he would make about 100k.
Let me just say, I think there are very few authors who can expect sales anywhere near those numbers. NYTimes bestsellers do a fraction of that.
Still, a busy author can easily write 2 to 3 books a year, more if the are organized, determined, and disciplined. Some authors that I know of are putting out a novel a month.
So, he can make a living. And he is MUCH better off without an old fashioned publisher.
As far as services needed, there is a burgeoning industry of freelance editors, cover designers, book designers, etc., that will provide everything a traditional publisher used to provide. OK, yes, except for a marketing budget, but talk to mid-list authors and see what publishers provided to them for marketing. HINT: nada.
How do I know? Without giving away all my secrets, I'm making way more money than I ever thought possible publishing fiction on Amazon KDP. I'm about to jump into non-fiction, which I'm guessing could be even bigger...