Real Estate / Australian citizen - Inheriting studio apartment in Warsaw [3]

Hi there, my boyfriend (Australian citizen) is going to inherit a 31 m² studio apartment in Mokotów, Warsaw. The property is currently in his paternal grandmothers (Polish citizen) and fathers (Polish/Australian citizen, deceased) name and she is hoping to sort out what he wants to do (sell the property and inherit the money, or inherit the property) before she passes.

I have done some basic research, and understand that Australia/Poland has a tax treaty, and there is no inheritance tax for foreigners (?)

We are in our mid-20s and assume the property has a sale price of 205,000 - 235,000 PLN (70-80k AUD). I am concerned there will be hidden costs because my boyfriend is not a Polish citizen/hold a Polish passport. I am also concerned that his paternal grandmother will pass before this can be finalised through the Polish court system.

We are concerned that inheriting the property may prove a nightmare and that the tax will outway the worth of the property/any rent generated.

I am looking for any generalist advice and any greater implications that inheriting property can have.

Thanks in advance!