FA,
About the in-laws, each case is so individual and only you know them and how to act and what to say around them. If you don't think you want to bring up the words MLC due to them probably not understanding it, then just keep saying what you were saying about your H being lost, and needing time to work things out on his own.

Many of the in-laws here get very upset with their MLC sons/daughters, and some refuse to talk to them. If the in-laws blow up at them, it only makes for a bad situation for themselves, as the person in MLC just doesn't want to hear it or deal with it due to their guilt.

My in-laws went to try and talk to my H when he left me the first time and we all had to find him since he wouldn't even tell people where he moved to. My H blew up at them and said to get the F away and that he wouldn't want to talk about the sit. for at least a year with anyone, and to leave him alone. Funny thing is, about a month later he started to reconnect with them and ask his parents all sorts of questions about their family history of depression and all about God, and he needed to borrow $ from them for the first time in his life because he went broke. Since then, he has only visited with them on big holidays or events, and he often will not stay long and never wants to talk about the sit. with them. So my in-laws have learned to not bring the topic up with him anymore.

I have told my inlaws all about MLC, I have even read them passages I found in resources that point out the reasons that I feel his is in a crisis/depressed. They were not so open to it all last summer, but when he left me again this winter - they finally started to say they feel I am right on, and they agree with him being depressed and are actually just as worried now as I have been about my H committting suicide. They are very nice in-laws, that are willing to listen and that feel really sorry for what my H has put me through. My MIL has even asked me the names of the books I have read on Depression so that she can buy and read them also.

Everyones in-laws are different, but it sounds to me like you have explained the MLC thing to yours in a good mannor. You basically are stating the facts about a MLC to them with out actually coming out and saying the words MLC. You are handeling it well. And remember you have no control over how your In-laws will react to all of this, if they come visit to shake some sense into your H, you can't stop them and it will be something that they have to deal with in the long run.
TIPPER