can't for legal reasons
As Grzegorz says, all EU citizens may live and work in Poland.
He may just not want to go back
He is more than likely making more money where you are (you didnt say where)
and doesnt wish to return for this (or other reasons)
But its not about legal reasons (involving work)
Taxation CAN come into it. BUT if yer man gets his finished working form in IRE/GB and goes back to Poland he is prob afraid of paying tax on earned wages twices. This just cannot happen.
There are double taxtation treaties between all EU countries. If he must subsequently pay Polish income tax on his return, he claims back the tax he paid in the IRE/GB.
hope this helps