Atheist DIL won't allow us to see our grandchildren

My husband and I are Baptist and raised our son as Baptist as well. He started dating a Catholic girl on high school, and while we were never entirely supportive of the relationship we didn't actively protest. He joined the military after graduating and now they live in Washington state (we live in SoCal). They have three kids together.

Before he graduated, he announced that he was an atheist. We thought it was just a phase, something he decided because he wanted to have premarital sex with DIL. We knew this was somehow something she convinced him was right. He was deeply religious and loved Christ before he met her. They are both now "out and proud" atheists. This phase has lasted over ten years.

Well, my husband has been vocal lately about his distaste for DIL and her corrupting ways on our son. He has made it clear that he WILL talk to our grandchildren about Christ, and encourage them to accept him into their hearts. When DIL protested to this, he said fine, we will do it when they're older (around 12). Again she got angry and said no. A few months ago during a visit, things got heated and DIL told us that we were not ever allowed to speak about Christ or religion to her children. My husband protested and she kicked us out of their home. I was so disappointed when my son allowed this to happen. What happened to honoring thy father and mother?!

Since then, there have only been a few phone calls between us and my son. The kids are never "available". We requested them for a few weeks this summer and my son only replied that that would not be happening. When asked when we can come visit again, or whether or not he and the girls will be coming down to visit us, he just says no. DIL is no longer comfortable with us having a relationship with them. My DIL has led my son away from Christ and is deliberately alienating my grandchildren from Him, as well as us.

I am so hurt and honestly have no idea what to do anymore. I am at a loss. I am so worried about my grand babies. I am considering contacting a lawyer about establishing grandparent's rights, although I don't know how that would work seeing as we are in different states.

Thank you for reading.