Wow. I don't try to change all of christendom. That's too big for me. I talk to individuals and explain it to them in a way that makes sense. I have this one guy that calls me and he is actually witnessing to his friends with his limited knowledge (still learning) of the Torah, etc..
To me, Gentiles were supposed to follow Torah. Everyone was supposed to. But, Gentile nations in the beginning had their own gods they worshipped along with their practices. Ruth is a good idea of this. She was a gentile pagan priestess that came to believe in the one true G-d of Abraham, Issac, and Jacob. She had to change to be accepted by her new society and by Hashem. In a way, this was how she found salvation. But, she couldn't hold onto and practice things she was taught in Moab. She had to ..separate.. herself from those things.
Separation from such things shows Hashem that you honor and love him. This is part of Torah. The Mosaic law was not meant for one race of people, but, for any that truly desired Hashem. This is hard to swallow for someone in most churches that I have met. It truly isn't keeping Torah that is important, but the desire to follow it and the one that gave it that is important....but keeping it is important , too.
I hear people talk of the law as if it is evil, cursed, and can't be kept. This can't be. It is pure as the one who gave it. It has it's purpose(s). It is very good. First law , don't eat from tree,,,,and the enemy said "Has G-d said?..." the law not to eat from the tree was pure..afterwards.....G-d's law can't be kept...same mentality I find out there all the time. Anyone could join the jews---but, they had to leave things behind, and most were unwilling.
So, Yeshua came to Israel. He desired that they would turn back to G-d with their whole heart. Gentiles came to believe in him, but lost the message that they were to return to the Father and obey the Torah from the heart. Instaed, they (not all) teach the son did away with the Torah and keeping anything Jewish. They act as if the Father and son have two different agendas and doctrines. This cannot be. They are one. They agree with each other in all things.
How can you pray in the name and authority of the Father if you blatantly refuse to do the things he asks? If you do those things he has had written that he detests? If you call his Law evil? That his son did away with it---so you have an excuse to be lawless? I see it all out there with some of the folks I meet. But, those that truly want to know? I just tell them. I just show them. I ask them "Do you want to do what man says you should do--or what G-d says to do". It really is a personal choice--and I am not responsible for which way they go...but, I just tell them--when they ask or the subject comes up. I don't go out on some crusade, lol. It's not my job in life. Some are sincere and call me with questions..which I try to answer..depending on what is asked. It's not hard.
I asked this one guy that was going to open up a truckstop ministry why they teach people on a 4th grade level..he said if they don't, they won't come..jeez, milk and honey..no meat. See, I talk to christian ministers too. And even when they know their doctrine is wrong, they will not separate themselves from it. how do you fix that? Many of these folks are like a "Ruth" that still wants to be a moabite priestess-I hope that example is ok. I meet so many spiritually weak people every day. After I talk to them, it seems like they pull their bootstraps up and start walking their walk. I even have people call me and tell me they were cussing me because they went to grocery store and saw those pork ribs----and it's my fault, lol. It's ok. They are seeing the scriptures in a new light. What is written without what people tell them it says..they are starting their own journey into showing my Abba father that they love him. And, they don't need me to hold their hand. Soon they will fly. Soon, perhaps a flock against the nightsky..but, it starts with telling one.
Temptinfates
I'm sorry to hear that this has caused division in your family. I too have experienced it and I think it happens everywhere. Like all relationships a happy balance is tricky to find, but worth working towards. 
