Employ Ukrainian refugee in Poland as a German company

Dear community,

We are an German SME and would like to employ a Ukrainian citizen in a 100% remote job within Poland. He has fled with his whole family (parents, wife, children) to Poland and wants to stay there and keep his residence permit. However he needs to be directly employed as we also receive funding for his job role as he is going to work in a partly governement funded research project. So is it possible to employ a Ukrainian refugee with a residence permit in Poland as a German company or are there any restrictions that would prohibit such a employer relationship. We have asked many people in several German administrative organization and nobody was able to provide a useful answer. So if you have any useful input with regard to the posed question I would be extremely grateful!