Question:
I am writing on behalf of someone who came to me (yes he's a Christian [guy]) concerned about how to approach his parents-in-law [un-equally yoked] who both have very different faiths. These two in-laws were once married twenty years ago but got divorced after having a child. Now they are back together and things were good at first, but not now. This child [Christian gal] is now married to this [Christian guy] who has come to me for advice.
The person says, "The (the mom) mother-in-law who is or was Christian--somewhat conservative, talks of Jesus a time or two, but it was so much more before the (the pa) father-in-law, a poly-theistic-Vedic (very liberal) came into the picture."
Now, the mother (the mom) wants out of the (not legally married; but they live together) relationship but always recants accepting him (pa) "because she's fat and lonely (her words)" and "oh well, he's around".
Question: This person sees their in-laws allot; And religion and values and issues are always brought up. How should this person [Christian] deal with each parent respectfully and what do you believe would be wise concerning the telling of the mother-in-law about God's plan for marriage [which I am told has already been brought up many times but to no avail]?
Thoughts? Questions? Thanks!
Answer:
I honestly don't know what (if anything) he should say. These two people are old enough to know what they're doing. They were also married before so they know the deal with the relationship.

It might be that the best thing he can do is remain silent and pray, unless one of them asks for his opinion.
Answer:
What a mess, seems to be the best way to handle the situation is too stay out of it unless asked for advice. If asked, I would recommend witnessing like neither were believers. Show them the plan of salvation and let the Holy Spirit do the rest.
Peace
Answer:
It sounds like there's a self-esteem issue going on with the mom, and that needs addressing. The pa seems as though he's fine with the arrangement and, apart from the fact he needs Christ, doesn't seem to be acting out of anything broken within himself.
That said, if things have already been brought up, it's not going to help to rehash things over and over. Instead, inquire as to why the mom is doing what she's doing - she's the one that probably has internal discord about the arrangement, at least if she looked deep enough. Not publically, of course, but privately. Also, this is not yours to involve yourself with outside of giving your friend advice.
Answer:
If there's one thing I've learned in the one whole year I've been married, is that sometimes it's best to keep your mouth closed unless specifically asked a question, and even then, it's good to guard your mouth as you answer.
Answer:
I am letting him read these online so he can feel the love and advice you guys have.
I counsel and often times, I recall the Bibles rich word, "In the midst of many counselors, there is wisdom" [Ecclesiastes]. You all are great and he confidentially thanks each of you.