50 Cent's not the cold-hearted prick he appears to be in that video with an autistic man -- so says a guy who got the best wedding present ever from him, weeks before the infamous airport incident.
The groom, named Chris Brown (yeah, we know) ... tells TMZ he was getting married at the Loews Hotel in Philly last month when word spread 50 Cent was also there. Brown found him and asked for a huge favor.
Brown's brother, Justin, is a Fiddy super fan who suffers from reflex sympathetic dystrophy syndrome ... which causes chronic pain and confines him to a bed. Brown says he asked 50 to meet Justin, who was in a room at the hotel.
He says 50 said he would "try" to make time, but had several events to attend ... so Brown wasn't sure it would happen. But lo and behold, the rapper showed up -- without an entourage -- and talked to Justin for more than 90 minutes.
Mind you, this was 2 weeks before 50 Cent's run-in with Andrew Farrell ... which Chris says is the exact opposite of his brother's life-changing experience.