you wrote "He is mentioned as a officer-aviator for the White Garde under general Dinikin and was supposedly a teacher at the former Austrian Hungarian court."
After reading this details I've realized, that all that is entirely possible and doesn't contradict my findings so far! The latest mention of K. being in Austria-Hungary I've found yet, is from February 1918. Tsarist general Dinikin joined the White Army after the October Revolution in 1917, and later even commanded this army in the Russian civil war (1917/18-1922) until April 1920.
In French newspapers K. seems to appear from ~1923 on. Therefore it is entirely possible, that he indeed was a military pilot in between, not in WWI, but during the Russian civil war, fighting for Dinikin against the Red Army. It would also correspond with K.'s mindset from 1940, with his "disapproval of the form of government of his country", if in the beginning he even had fought in the White Army against the Red Army of the Bolsheviks.
Also, there is evidence, that in 1910 K. has taught at least two Austrian archdukes. They even seem to have granted him a diamond pin, as well as the right to officially use a corresponding title (this was in the same year, but AFTER the incident I described above in an earlier posting). Certainly that could have been expressed as "having been a teacher at the former Austrian-Hungarian court".
So it may well be, that THAT questions CAN be asked, in K.'s case at least.
BTW, one Kasulakow Wladimir seems to have been married to a Hungarian woman, with which, by August 1917, he had two children at least (Kálmán and Erzsike
). The father in law, Fehérváry József, seems to have been Roman Catholic. If this Kasulakow was our K., perhaps his family, or a part of it, accompanied him to or joined him in Holland.
OTOH, I found some mentions of an Elisabeth
Kasulakow or "Kasulakow ép. Van der Sman, Elisabeth
" (born in 1917?) from the Netherlands connected with the resistance, and also mentioned in a Holocaust Survivors and Victims Database (regarding Ravensbrueck, IIRC). Perhaps there really is a connection?