Giovanni,
I would suggest obtaining a copy of Piotr's death certificate.
Rabka is a town in Małopolska voivodship (Rabka-Zdrój parish), it is indexed, Ignacy is not there (maybe his birth certificate is in a town not indexed - no books? - but belonging to Rabka-Zdrój parish)
There are several Piotr Wojtowiczs, but, none of them seems to fit:
https://geneteka.genealodzy.pl/index.ph ... rdertable=
Maybe not Legnica but, e.g. Lednica? Or another town in the Małopolska voivodship?
Pozdrawiam.