Travis Saunders, from Australia, who blogs at School of the Road, called the moment one of his “greatest” successes to date.
His son, Patch, is severely autistic and Saunders said one night they were going through the process of getting him back to bed for the “upteenth time”.
“Out of the blue he started laughing,” Saunders wrote on 29 August. “So what did I do? I started acting a little mischievous and silly because I knew it would make him laugh and feel happy and in turn make me feel really happy.”
Saunders continued: “And what happened next was incredible.
“A few minutes later, he very clearly spoke to me and made a comment about what we were doing.
“He simply said: ‘You’re funny’. Now I can’t express how amazing that makes me feel as my son is mainly non-verbal and has never said those words before. He’s certainly never ever made a comment about something we were doing together.
“And let’s face it I’m not funny but I’m a dad and most of them think they’re funny, so why can’t I?”
Saunders shared the heartwarming story alongside a photo of himself and Patch jumping on a trampoline, adding: “I reckon we’ve spent more than 1,000 hours jumping together.”
Commenting on the post, one person wrote: “What a great reward. This warms my heart.”
Another wrote: “How wonderful is this? Truly people should never use the ‘never’ word. Love this very special father and son moment.”