The baseball player, who dated the 22-year-old singer, sent an email to Bobby asking to let him attend his girlfriend's funeral on Saturday, reported TMZ.
"I loved Krissi with all my heart and I am destroyed that she is gone and I need to say goodbye," he wrote.
Kristina, the only daughter of Bobby Brown and late singer Whitney Houston, died on July 26, nearly six months after she was found unresponsive in a bathtub at her home.
Gordon, who was raised by Whitney but the singer never formally adopted him, was probed during the investigation over Kristina's condition as the family never approved of his relationship with Kristina.
"I'm begging you both to please put your differences aside and allow me this chance... Krissi loved me very much and she would want me there."
Kristina will be buried next to her mother in Westfield, New Jersey, at the Fairview Cemetery on Monday.