I understand what you are saying, Velika, and each LBS definitely has to make his or her own decisions about whether and when to divorce. In my case, it would have been far worse for D and me, financially and otherwise, until she was out of school and during several medical situations where I desperately needed H's much better health insurance, but each case is uniquie.
I'm not sure if you reside in the US, but a therapist or a doctor would never allow a spouse to call and speak to them about a patient. I can't even do that in regards to my daughter without her first granting permission for her doctor to speak to me without her knowledge. And legal adults (over age 18 in the US) have the right to make their own decisions about what tests and screenings they want unless they are genuinely so incapacitated that a court grants that authority to another person.
Even my neighbor with a 19-year-old autistic son has to speak to his doctors in front of him at all times, and is not always allowed in the room (and never during counseling) because he is considered high enough functioning though he could never live indepedently.
Even if I was to have called and "alerted" H's doctor of a change in personality, this would have had no bearing. As completely bizarre as H acted in front of me, he held it together just fine in front of others (and 7 years later, still does) and his doctor would have thought I was a woman scorned trying to make him seem crazy. If anything it would have given credence to others about why H wanted to leave. As difficult as it may be not to have control, we don't. However, if a degenerative issue is at play, either a spouse will choose to get help or it will naturally progress to a point that it's obvious to other family, co-workers, etc. that they need help. It may not be ideal, but this is what the law is in many places which is why it only adds to the stress, and maybe guilt, to tell an LBS they have to get a spouse to an neurologist or other doctor. That can't be done against their will in many places.
I agree that people should consider possibilities when a loved one has sudden and drastic changes in personality, but--depending on the laws and policies in each area--this does not mean that the spouse has any say or influence in the situation other than to broach the topic with their spouse in the hope he or she might choose to look into it.
Phoenix