Not personally, no. Sleeves will hike up on a bike, yes, but I don't think he's wearing that coat on a bike. If it's a daily wear piece, I'd shorten them. Hell, if it was a functional piece I'd still shorten them.
Sleeves are definitely too long. If it were me, I'd take it to somebody experienced with working with leather (not a job for a dry cleaner seamstress) and have them knock at least an inch and a half off those sleeves.