Do they arrange for someone else to put candles on their relatives graves in Poland?
if family (in Poland) can't get across country they visit a local cemetery and place candles and flowers at the cross, which serves a number of purposes including a place to lay wreaths for those buried elswhere or those lost with no grave (victims of war etc)
sometimes people will place a candle on an untended grave.
some folk contact other family members and come to some sort of arrangement.
some simply go another day.