MLC is a long process, that W has to work through on her own. Does MIL understand this? MIL's meddling, no matter how well intentioned, can easily make things worse for you guys. This is why Michele tells us to NOT tell the family.
Having said that, I think it's great if MIL really understands the process, won't interfere or tell others, and can support YOU.
M: A really long time. Crisis: 5 years. She's still worth it.
Life is never made unbearable by circumstances, but only by lack of meaning and purpose. -Viktor Frankl