A competitive analysis is more properly done by the author, because otherwise the publisher would have to know EVERY book by EVERY publisher that is similar to a proposed manuscript that is new and unique to the publisher. After all, the goal of every author is to write something that's different than everything else. But, of course, there's nothing new under the sun, and it's much easier for an author to have an idea of what else is out there similar to their own book than for an acquisitions editor to have an encyclopedic knowledge of every book on the shelf.
So, that said -- what does a competitive analysis entail? Well, a memoir is slightly different than your average non-fiction. Most non-fiction are either self-help or how-to books, and it's quite easy to pop by your local library and search "divorce" in keywords and come up with a whole list of books on the shelf that are similar. But a memoir can't be so easily defined, so you'll be given more slack in this section. What might be useful is to search for the SUBJECT of the memoir. For example, if the story of your friend's life is a rollicking career as a merchant marine, then search for "merchant marines" at the library or bookstore and look for those with descriptions that include "memoir" or "life story". Even if you provide one or two, it will show that you've done SOME research.
As for a marketing analysis, this is quite simple. If you sit down and really think about it, who is the most LIKELY group of people to buy your friend's book? Yes, it's lovely to say that EVERYONE will want it -- and that might well be true. But really think about it. If it's about merchant marines, will 20-something college girls pick it up? Hmmm... probably not, unless it's as a gift for a father or grandfather for Father's Day or Christmas. So, that's a market. Men from 50-70 will like the book. They've been through a war or two, have heard of merchant marines and might like to read someone's story about their own experiences.
See where I'm going with this? Think about the two or three things in your friend's memoir that makes it so intriguing and decide who is MOST likely to want it, and why. Then pop by the U.S. Census Bureau's website and see what the "demographic" is. A demographic is a quantity of people in a certain class. You can look to see that there are X number of men between 50-70 and X number were veterans. Write down these numbers and send it along, and include the group of CURRENT military (since they might be interested too.) That's pretty much it for the marketing analysis. It doesn't have to be much more than a paragraph. The editor isn't looking for you to sell the book, but they want to get a feel for who might BUY the book so they can see if it fits their line.
Does that make sense?