Oops - went off on a jaunt and forgot to address the question, lol.
Planting seeds is what we do... so, no, you're not wasting your time by showing them real Christian attitudes. If the inculcation is deep - and the wt pumps them full of fresh vitriol at every meeting - then it'll take a lot of seed-planting. It's never a waste when all you're doing is letting your light shine and showing what real love is - what it looks like, how it acts and talks - how it feels. Seriously - they are taught to oppose love since, 'the heart is treacherous'. wt doctrines are a hot twisted mess... not really Christian, actually.
So if you think you can swoop in and save them all from the cult - which we'd all love to do for our loved ones caught in it's web - that's probably not going to happen... but who knows how those little seeds might grow, even in those adverse conditions some seeds may manage to sprout!
Happy planting!
Watkins