In September 1941 Sikorsky was heading "Provisional administration of the Ukrainian Orthodox Church" in Volhynia as Archbishop of Lutsk and Kovel eparchy (diocese).

By decree of Metropolitan Dionizy (Waledyński) of 24 December 1941 he was appointed to the position of provisional administrator of "Orthodox Autocephalous Church on liberated lands of Ukraine".

Sikorsky initiated the 1942 Hierarchal Assembly in Pinsk which became important in reforming the Ukrainian Church.

Soon thereafter the Nazi security officials searched his house and arrested and later executed his assistants Maliuzhynsky and Mysechko.

After the German capitulation he resided in Gronau, North Rhine-Westphalia and later Bad Kissingen, Bavaria.