The Real Madrid goalkeeper met him during this summer’s European Championships in Poland and Ukraine as he was a massive fan of the 31-year-old shot-stopper.
A message from the player will be broadcast on Polish national television and he has provided the family with a Real Madrid shirt with which he signed: “Dawid, always with you” in Polish.
He added: "I dedicate this to you with so much love, for them to keep it and always have you in their memory."
This mark of respect is in conjunction with Ryszard Schnepf, who is the head of the Polish embassy in Spain. The event took place at Real Madrid Football City this week where Casillias said: "Firstly, I would like to reiterate my condolences for the family. May Dawid rest in peace.
"I had the opportunity to be with the family in the last European Football Championship in Poland and Ukraine.
"I was there at the same time as him in Gniewino for two days and he was a person raring to live life to the full, so happy to meet Spain's national team.
"He had his photo taken with all the players, and his parents, family and friends were happy with all of us."
Casillas explained that he takes his responsibilities as a role model seriously and that those who have admiration for him deserve affection and consideration in return.
He went onto clarify how he became aware of Dawid’s story and how he wanted to help.
"His mum went to our federation delegate," he continued.
"The story caught my attention. He was a boy who wanted to meet us and meet me. He gave me a small present, a teddy bear. Then we spent a few days together where he would become close to us. He was very happy, as were we. The fact we were with him made him so happy, imagine what that meant for us."