Sure feel free.
How much he'll get will depend upon exactly what he has, and how he groups it for sale, and how he presents it.
There are tricks to getting better prices when auctioning on eBay or other auction sites, simple stuff that makes your auctions sell for quite a bit more.
I want to make it clear that I'm not trying to discourage anyone from trying to make a little money on their comic book collection. I just wanted people to understand that making money on comics as an investment is very difficult. It is a good way of getting some quick cash in an emergency, but you're very seldom going to get anything anwhere near guide.
A lot of people will look at their run of, say JLI 1-113, see them priced in the guide at $2-4 each and think they've got a run worth $500. That run would actually go for about $100 most of the time, not bad, but nowhere close to Overstreet or Wizard value.
Good luck to your friend, and if he's going to use eBay, tell him to check the comics message board
FAQ.