Visit -http://aydnajimudeen.blogspot.com/- It is not permissible to congratulate the kuffaaron their festivals in any way whatsoever.

What is the ruling on eating the food (rice, meat, chicken or cake)
that is given to us by a Christian friend that he made for his
birthday or for Christmas or the Christian New Year? What is your
opinion on congratulating him by saying, "Insha Allaah youwill
continue to do well this year" so as to avoid saying Kull 'aam wa
antum bi khayr (approx. "season's greetings") or "Happy New Year"
etc?.
Praise be to Allaah.
It is not permissible for aMuslim to eat things thatthe Jews and
Christians make on their festivals, or what they give him asa gift on
their festivals, because that is cooperating with them and joining in
with themin this evil, as is explained in question no. 12666 .
It is not permissible for him to congratulate them on their festivals
inany way whatsoever, because that implies approval of their
festivaland not denouncing them, and helping them to manifest their
symbols and propagate their innovation, and sharing their happiness
during their festivals, which are innovated festivals that are
connected to false beliefs that are not approved of in Islam.