I don't remember him..
Short Kingdom Hearts: Goofy Fan Fiction

Characters:
Sora Donald Goofy and Max Goof is referred, but doesn't appear.
and this takes place during KH:CoM.

While Sora, Donald and Goofy were walking through a hallway floor in Castle Oblivion, Sora mentions something.
"Hey, Goofy... didn't you tell me you had a son..?"

Goofy stops, thinking for a second. "Uhhh.."
"Gawrsh, I don't know.."

Sora still asked. "But DO you have a son? My mind's getting fogged up for some reason.."

Goofy looked confused. "I..don't remember him... I..think his name is...er.. Maxa or Maralle or.."

Donald and Sora also looked confused. "But.. I thought you..had a son..?" Sora stared at him awkwardly.

Goofy shook his head. "I probably don't. Probably just something we faked up, but still the memories most close to us.. we'll never forget it! Ah-hyuck! Right?"

Sora nodded, smiling. "Yeah, you're probably right.."

Donald began started to get impatient. "C'mon guys!"

Sora turned to Donald. "Coming!" then back to Goofy. "Goofy.. just try not to lose those important memories."

Goofy chuckled. "Ah-hyuck! Don'tcha worry!"

Both of them nodded, proceeding through Castle Oblivion.