[TLFisher]

I would agree a professional Christian counselor or at least a professional Marriage counselor.
Beyond professional counseling, there should be no third party interference for this sister and brother. No input from children, parents, relatives, nor ones from the Local Church.
I've heard of too many cases of LC brothers advocating reconciliation or divorce. Pretending to be professional counselors which they are not. Further more to give any weight to "what the brothers say" is the same as saying the brothers have replaced God as the head. Too many voices make reconciliation that much more difficult. Just as many will advocate staying together as there will be ones advocating divorce. It is best for the couple to reach a decision without anyone else's input.

I don't know how many years they've been married. Longer perhaps the better to suggest to remain married even if one spouse wants to remain meeting with the local church and one doesn't. My father is 80 and hasn't been meeting with the LC for the better of 40 years whereas my mother continues to do so.
When my uncle and aunt were meeting with the LC, it was quite common for my aunt to remain home or just attend for the Table meeting and leave before the Prophesying meeting would begin. I'm sure there are other marriages did quite well without both spouses participating in LC meetings.