Technically speaking, if what you did in the past will also have an effect of the future (not the same concept with the Avengers: Endgame Time Travel concept). However, the reason J remembers K is because coming Jeffrey, “you (J) were there”.

Why is J the only one who remembers K?

Technically speaking, if what you did in the past will also have an effect of the future (not the same concept with the Avengers: Endgame Time Travel concept). However, the reason J remembers K is because coming Jeffrey, “you (J) were there”. With the timeline restored, Griffin is once again seen in the diner with J and K, who are seemingly still friends with him on the new future. He then refers to the audience stating that everything turned out alright and says that this is his new favorite moment in human history. K later requests that Agent J erase K’s memories of his time with the MIB so that he can reunite with a woman he had loved before joining the MIB.

Did K take care of J?

James Darrel Edwards II Agent J never really knew his real father, as K spent the majority of his life taking care of him, and keeping his father’s death a secret from him. J’s father, Colonel James Edwards Jr. was killed at Cape Canaveral on July 16th, 1969, by Boris The Animal when assisting Agent K. Colonel James Darrell Edwards II is Agent J’s father and a minor character in Men in Black 3. He is portrayed by Mike Colter. At the end of MIB 3, it was revealed that J and K met when J was a young child. After James’ father died assisting the MIB, K had to neuralyze J who then went on living thinking his father abandoned him. It was implied that K had been watching over the young James for his entire life starting at that point. MIB3 ends after a time travel expedition, in which J finds out that K met him as a child after J’s father died and that his father was killed by an alien right in front of K. K neuralyzes child J of that particular moment, and continues to be someone who watches over him. Headquarters and learns who Boris is, but before he could learn more, the Agent in charge, O (Dame Emma Thompson), stops him. The next day, J goes to pick up K, but finds someone else living at his apartment. When he goes to M.I.B., he looks for K, but everyone there tells him, K died in 1969 after tackling with Boris.