My sone us citezen student his shengen czech visa...

We would like to inform you that the period of validity of a Schengen visa for a foreigner residing in Poland issued by the Polish authority or another Schengen state authority can be extended, and it is also valid on the territory of Poland in the following cases:

-If they prove that it is impossible to leave the country as a result of force majeure or for humanitarian reasons.

-If they provide evidence of significant personal reasons justifying an extension of the validity period or the period of residence.

Note: The period of stay in Poland on the basis of the extended visa must not exceed the maximum period of stay provided for a particular type of visa, around 90 to 180 days.