Any chance of letting the RSPCA know what you know about these people...
puggerup, one brother probably thought the other brother would do the right thing by his dog. Dunno why, given the history.
I'm out all day tomorrow and a dog walking friend offered to mind my evil hound for the day with her dog, but I know what my dog is like at new peoples places or even familiar peoples places when I'm not there. I wouldn't wish her bad behaviour on family let alone relative strangers.
Interestingly I'm out at a dog training seminar, and it was mentioned several times that a dog might be well behaved for their owner and completely ignore anyone else.