Aleksander Żelawski IR 15

[egon]

Hello, I’m Mark from Poland.
My great grandpa was Austro-Ungarn troop from Galizien (Belz, Sokal, near Lviv).
He belonged to K.u.K. 15 Infanterieregiment and I think he fought over Isonzo River, because he
sent his last postcard from feldpost 55 on 9 August 1916.
Last trace I have is verlustliste nr 579 of K.u.K.Kriegsministerium from 24 May 1917,
but there is note that grandpa was wounded (not missed, not died).
Last year, War Archive in Wien confirmed me that grandpa isn't on any list of fallen, but there is any more documents and they can't help me.
Is it possible to find my grandpa??
Could you confirm where Feldpost nr 55 stationed?
WhatAleksander Żelawski area FP55 operated? Where was the central of FP55? I'm not sure, beacuse some people say that it was in Tirol, others say that it was over Isonzo...
Where IR15 or other polish battalions stationed on 1916-17?
Please, take a look at attachments.
Thaks for reply and best regards.
Marek Żelawski