The alternative is to find a guild that’s not trying to rush content or push any particular playstyle on your friend while also having the patience to wade through dungeons without playing efficiently. They’re definitely out there… though might be hard to find. RP servers are a pretty good bet for this.
But any chance of this happening organically with a pug is basically… not going to happen. Ever. He’ll need to grow his own community if he wants to avoid all the negative interactions you listed in the OP. As a youtube video once stated, “It’s rude to be bad at World of Warcraft”.