I was very indesisive about buying freelancer. I wasn't a big fan of space sims at all. I brought it beacuse it was open ended and promised much to explore. After playing lots of morrowind, i needed something where i could go out on my own for a while and just explore. The mouse control also pulled me in. I'm a bit of a spanner when it comes to complicated controls and reading it was mouse only i knew i could play it.
What i didn't count on was the SP storyline. I have played the SP from start to finish more times than i can count. Being the type of gamer that i am, i now really only buy a game if its going to have a good story. Although i do, on the odd occasion buy what i call a relaxing game, like Manhunt. No real logic behind it but very funny to play.
I would lend your friend your copy of freelancer(after you've played it too bits
) and tell him to play through the SP storyline. I'm sure he will enjoy it. However, as others have said, if space sims aren't your thing, no point in really trying to get him to like it.