Jimmy in church with his father, Barry Mizen. Margaret Mizen thanked the family's fellow parishioners for their prayers and support.
Jimmy and his youngest brother George at London City Hall. Barry Mizen said of his son: "He enjoyed life. His loss is immense, not only to us but to all his friends
Barry Mizen said his youngest, George, has been unable to sleep in his own bedroom since losing his brother.
At more than 6ft 2in, Jimmy's family described him as a "gentle giant". He died the day after his 16th birthday.
Jimmy was described by his mother, Margaret Mizen, as a loyal friend and loving son. She said he was the first to offer his seat on a crowded bus and tended an elderly neighbour's garden.
Jimmy was the second youngest of the nine children in the tight-knit Mizen family. His mother called him the "shining star" of the family.
Barry Mizen said his family's faith in God had helped them avoid a descent into anger over their son's death.