Luc,
Apparently left Belgium with others helped by the Comète Line. His name mentioned here:
https://www.evasioncomete.be/fvandaema.html
In an online book
"Les Aviateurs belges dans la Royal Air Force" by Mark Donnet it transpires that Drossaert was injured on 10 May 1940 in the bombardment of Schaffen by the Luftwaffe.
According Cornwell's "
Battle of France Then and Now" H-28 was badly damaged on 28 Feb 1940 at Schaffen, with pilot Drossaert
unhurt Evidently wounds sustained after all if hospitalized a day later.
Groet,
Leendert