Not sure I would use brown ones, but if they seem to smell OK might be worth a try.
Still think I would try to test them some how before committing to a full batch. Maybe toss a few cones in bottle of malty beer and dry hop for a couple days or do a small extract brew to check boil flavor. Even a hop tea.
Does your friend know what kind of hops they are suppose to be? Would be helpful to know if they smell and taste like that variety.