imm 5645, forget the deceased date of parents and the birthday and the address of brothers and sisters

[joyway]

Hi,
I am going to fill imm 5645 form(family information) , But I do not remember the deceased date of my parents. I also can't remember the birthdays and addresses of my brothers and sisters. I lost connection to them. Can I just fill in the name of them and leave the other information blank?