I would not expect too much of Igor if he does not bike. If he is as fit as you say he is it will certainly help his biking but then again he maybe a little nervous on a bike and therefore will likley be a little tense. As you know this does not help when riding and will hinder his abilities. Also rollerblading is a totally different skill than biking and uses different muscles. I would suggest that you take him out on a fairly easy ride and see how things are going and then if all is well and he is feeling comfortable then take him and show him the hill and see what he thinks. You could at least start up it and if it is too hard then turn around and take the ride back down.
I would hate to take him out and turn him off cycling by doing a hard ride. If he likes it you may just convert another person in to a cyclist.
Good luck and I hope the turkey turns out.
Mike