Has anyone ever had any success in suggesting reading of this sort to an mlc spouse?
Not that I have ever heard of. There are no shortcuts through an MLC. No easy buttons or magic wands. The people that I know that have made it though have felt that they are going to lose everthing in there life. They hit rock bottom and then and only then would something like this make any difference. Someone has to want to get better, nothing YOU do is going to make them do it.
MWD did not write that advice for you to ignore it IMHO.