That is an argument without any truth or logic. What if I claim that Angela Merkel encourages their migration to the EU? Unlike your post, mine can be backed up with actual proof.

Putin has nothing to gain from Muslim immigration to Europe. A Muslim majority Europe will be even more hostile to Russia. Also, it will affect the chances of the European pro-Russian parties, such as the FN in France, FPO in Austria, AfD in Germany and PVV in the Netherlands.