Heather, "Quite some time" depends upon the person in crisis. I can't tell you how long he's going to be irrational and doing crazymaking things. Some a year or two and others...3 or more years and then some never recover. Again, it depends upon the individual and his/her crisis and how THEY handle it.
I think 2-7 is average with 2 being a very short crisis. Laura Munson's husband was a year, but I think that is abnormal.
I think 5 years is more realistic but as Snodderly has said above some never recover. There are no guarantees that is for sure, most LBS's give up and say that their MLC'ers are stuck.
Best to follow the rest of her advice and not worry about it.