I don't think Breuer is good source for the inside info. It doesn't seems likely that after having a good relationship for 36 years, Angus would just tell Brian to f... of, and than Brian would whine to Breuer - too soapy.
Also, replacement singer = bullshit!
I don't want to upset hardcore fans but since the 80's AC/DC is Angus and Brian. Their biggest change was retirement of Malcom. If Phill Rudd also retired instead of being pulled in the media, nobody would get upset really, and same can be said for Cliff Williams. I don't mean no disrespect for those 3 (Malcom, Phill and Cliff) but an averege concert goer couldn't notice the replacement. But Brian on the other hand...
I wish they sort out this between themselves and do this last leg of tour proper - Brian and Angus side by side. If it's not meant to be, just call it quits - after 40+ years they don't owe anything to anybody...