It’s tough being the offspring of JW parents. The religion demands conformity, it cannot demand that everyone believes what it teaches. You have had the great sense to see the errors of JW beliefs but your parents are encouraging you to conform to the Org by being normal parents i.e. helpful.
You however feel trapped in doing things you do not believe like publicly teaching Armageddon. On the one hand you don’t want to upset your family but on the other they are forcing you to go against your conscience.
Could you talk to your parents and explain that it is a "matter of conscience" that you can no longer do things which you do not believe in? You might preface the discussion by asking them, how would you feel if you were asked to do something contrary to your beliefs, would you do it for the sake of appearances?