Catholic funeral of a close relative- from Poland

a polish friend of mine has just lost his uncle -he was very close to him- he is in poland i am in the uk-he is very upset about his loss- i what to say/ do something to help him through this sad time but i am not sure want will be correct. i know my friend very well but i do not know and have not met his family-can someone advise me on this -should i send a sympathy card? flowers? is there a typical mourning period?-i want to show my concern but i obviously do not want to intrude upon a sombre family situation

ohh how sad.

I think the best is to call your friend and talk to him , it helps to have
friends and someone to talk to . Also you can send a card with condolences .
Just let your friend know that you are his friend. That is the best thing to do.

yes it is sad

-i have spoken to him several times and sent sms to tell him i understand his saddness and i am here for him-i just wondered if there was any special polish phrase which is said in these circumstamces?