that sounds like a classic case of a dominance problem... if the previous biting incidents were due to the same reasons,, its defiantley dominance,,, I suggest classes of course,, but a good way for your brother to tell the dog HE is higher on the totem pole,, have him attach the dogs leash to his waist and lead him about the house as he goes about his usual business. Do not pay any attention to him the whole time but offer plenty of praise after say,,, 20 mins of this everyday for the next while.. Also,,, do you place the dogs food out all day or do you have a certain time for feeding? Putting the dogs dish down all day is bad.. Have your brother feed the dog,, 2 times a day placing the dish down AND taking it away each time. Put the food out for no omre then 10 mins or so. Always make the dog WORK for everything,,, There are NO FREE LUNCHES as the saying goes.. A mere sit down,, or giving of the paw is good,, but always make em work.

Hope this helps some...