I have some information about a Christianus Boers also from Deventer and he must have died 1795/1796. This is the information I have:
He married in Colmschate (near Deventer) 22-08-1795 with Willemina Klinkert. He was widower from Grada Jansen. (He must have died soon after this marriage because his widow Willemina remarries in august 1796).
At the Roman Catholic church they mentioned his parents names:
Conradus Boers and Maria Driessen
http://www.vpnd.nl/bronnen/ov/colmschate/colmschate_trrk_17841804.pdf
At the notice of marriage they mentioned his birthplace, "Heelde". Later I discovered this must be Heerlen in Limburg.
http://www.vpnd.nl/bronnen/ov/colmschate/colmschate_124_trciv_1795-1796.pdf
His parents (Johannes Conradus Boer/Bauwens and Maria Driessen) married in Heerlen at 24-10-1728 and there was born a Joannes Christianus in Heerlen (RC baptized 25-11-1742)
I don't know if this Christianus is the same as the one you are looking for.
I saw that one of the godparents of the children of your Christianus was a Petrus Boer. My Christianus had a brother Petrus, baptized in Heerlen at 03-06-1746. I haven't found the marriage of Christianus with Grada Jansen, so I don't know if he was married before with Engberdina Albers.
Carolina