This discussion has come up many times. According to RCR, you can have contact with a vanisher, it's rare but it does happen.
Direct from RCR...
What Contact Type is your MLCer? These are unrelated to whether an MLCer is high-energy, low energy, Antihero or Accommodater.
Boomerang
This MLCer stays in contact--sometimes because you have children, but not always and often the children provide a convenient excuse. The contact may be Monster spew, it may be clingy and seeking reassurance, it may be cake-eating, but even when it seems they will just go away, they bounces back.
Off-and-On
This MLCer contacts in small bites, perhaps an email or other contact every few months. Touch-n-Goes are smaller or shorter than with a Boomerang. It may feel like a reopening of old wounds with each new contact which may increase during special dates and holidays. They may send gifts but offer no information other than a note--or may send no note. Touch-n-Goes where there is two-way communication are often tests and feelers to determine how you will treat them, what you want from them and whether you are judging them.
Vanisher
Is my spouse dead? You may know they are alive and how they seem to be doing because of the grapevine, or you may not. This MLCer seems to drop off the earth. They may contact on occasion, but contact is rare. Do not pursue, if you try to contact or follow your MLCer they will find a new hideout and bury themselves deeper, and blame you more. By leaving them alone you are allowing them the time to heal and to choose how they will heal even if you disapprove of their choices.
Like so many things, the Contact Types run along a spectrum with Boomerang at one end, Off-and-On in the center and Vanisher at the far end. MLCers may move on the spectrum--though they remain relatively static most of the time. When they move, they usually stay in a contact type for long periods. Some are Boomerangs in early and even late MLC but may Vanish once things seem finished--the divorce is final and either of you may have a new relationship. This may include vanishing from your children's lives.
Nas and I (and others) are good examples of having rare contact with our vanishers. I really don't think how the contact/no contact happens really makes that much of a difference unless the LBS makes the contact impossible, Yellow did not do this. Yes, she made it a challenge but not impossible. Also, if the MLCer did not want contact, he would not have responded.
This guy is a stereotypical vanisher (the absolute no contact for life exists but are extreme and rare) and he responded to contact,...how? Semantics. So what if it was by Yellow's request, like I said before, I requested for The Leaver's help close to BD, it was a big deal, my exact words were, "I'm afraid to leave the house and come back to find (son) hanging"...
No response. Years later I would challenge The Leaver in a message, and he would respond or call. It was about timing.
Yellow's vanisher probably would not have responded to her request years ago but he more than responded, he showed.
It's kind of a big deal, IMO.