I don't know her personally but I did some digging and found an address. I don't think it would be appropriate to share that here, if at all (although I have shared David's contact information with a few others here, with David's permission). I was told the sister-in-law is working with some people already. I have no insight into who, whether there are issues (other than the lost disk), or anything else.
You'd have to ask the leadership that question. I can't speak for them. Please bear in mind I only did the work to get in touch with David to answer the "what happened to the Handbook" question here. I never had any intention of going beyond that, although I don't mind being a conduit to convey status from David if he chooses to update me from time to time.
All in all, I have to agree with the earlier statements and inferences that the handbook is a nice compilation of information, but all that information is available out there from other sources if one looks for it. I bought a copy a while back, read it, and got very little from it that I had not already seen here and elsewhere.