The language is changing. The historical object case (“him”) is expanding in the spoken language at the expense of the subject (“he”) and possessive (“his”) cases. This creates all sorts of confusion: people rejecting the old system as prescriptivist or a fake rule borrowed from Latin, whether that’s correct or not. People rejecting the new system as incorrect or grammatically illogical. But it’s just a change.
“Me and him hate them telling us about it.” That grates on my ears, but people genuinely speak like that, and it’s understood.
The pronouns have been in flux for the entire history of the language. Replacing the Old English “heo” and “hie” with “she” and “they”; ditching “ye”; ditching “thou”; sometimes adding “y’all” and variants. Using “you” for the subject used to be just as wrong as using “him” for the subject.
So there seems to be a new rule for the gerund, where the object case is used before a gerund rather than the possessive, just as the new (weird) rule about “and” taking the object case.
I prefer “his telling,” but it is starting to sound wrong to people, which is the first step on the road to archaic → obsolete.