Really, Cris doesn't do anything drastic, in earlier days if he found Oliver in a spot he is not supposed to be he would pick him up and put him down and say NO, well, I would do the same but Cris can do it in much more decisive and authoritive manner. Then when he was particularly naughty (jumping on the dinner table and trying to swipe at the food while we were eating, or repeatedly jumping on our billiard table) he pressed him on the floor and held him down for some moments until he quieted down a couple of times, but I read this sort of disciplining is one of the most effective as it is the manoeuvre used by mum cats when the kittens are small. These days it is enough for him to approach toward him with a slightly threatening manner Oliver would drop what he is doing and bolt. It also seems that he is rather intimidated by bigger people, Cris is fairly good size with 182cm/nearly 90kg (6ft 1/14stone) though not enormous, this may or may not have something to do with it.
As you suggested, I told him to take over the daily care routine involving food for a while, I guess I will have to insist on that and see what happens.
Mary, my strategy with the guests are the same, it is no good when they take an excessive interest in him and try to reach out to him, he will just hide further and further. If they leave him alone and pretend that he doesn't exist, he will come out and hang about after a while. He is slowly improving with the visitors, yesterday a friend of ours finally managed to pet him for the first time!!
Cris had a cat when he was a child too, and it is not that he doesn't know how to interact with cats, but also Oliver is naturally a very timid, shy boy, we are hoping that he will improve on that as he grows.