What is the ruling on a resident in Europe helping his friends residing in Muslim countries to emigrate to Europe, knowing that his residency in Europe is temporary?

It is not permissible to emigrate or travel for tourism to the lands of the disbelievers, due to the Prophetic prohibition against a Muslim residing among polytheists, and the abundance of evil acts and trials therein. However, traveling for the purpose of inviting people to Allah is permissible, provided that the caller is safe from trials. It is not permissible to assist anyone in emigrating to the lands of the disbelievers except in cases of extreme necessity, or if one is going for dawah with the intention of returning if he feels harm or his mission ends.