Welcome...
Until someone wants to leave the "truth", there's not much you can do to make them listen to real truth about the "truth". Showing them all the scandals and information in the world about the WTS and JWs will only cause them to pull closer to the organization out of fear of apostate messages.
The best you can do is to drop small hints and subtle bits of information from time to time. It may not even be committed on at the time, but maybe later it will create a paradox or conundrum and cause them to think and doubt.
Even then, if they are really indoctrinated, it may not work.
Don't force the issue. If they're willing to continue to associate with you as a family member, it might be best to just enjoy their company and leave religion as an unspoken thing. Maybe in time, one of them will ask your feelings and opinions and you can tread lightly on a subject to make them squirm.
Again, Welcome and good luck.