Look to your own club rules. If you have to be a member of the club to race, use the club discipline procedures to get rid of him. Going to rule 69 or other ends up involving everyone and you guys lose control of the situation.
If he is going to sue, he will sue so hiding from doing anything out of fear of a court battle will result in him being the only member of the club left.... So maybe the other option is to start a new club (Club 2.0), accept the old members of Club 1.0 except Mr Problem. He can remain at club 1.0 by himself. He should be happy as his performance would improve.