We all have advise to give when friends and family have "difficult" kids. We feel that if the parents would just get their act together, the kids would be fine.
But there are many problems with children that are not easily "solved"; ADHA, autism and Asperger's are just a few. These problems seem to be hereditary or biologically triggered, and not a result of parents' behavior.
it is important for grandparents and Aunts & uncles to educate themselves and become part of the solution. Negativity only makes things worse. Love and acceptance of the child (not inappropriate behaviors) is very important! There really is some truth to the adage that love conquers all. Setting limits calmly, letting the child know how much you love them, goes a long way toward learning to control disruptive behaviors.
There are many Web sites that offer helpful information, but Web MD has extensive information.