She could be having hormones and the attack on your friend is her being protective of you, because you're her family. Has your friend changed her hairdo or perfume or anything? Quakers object to changes. Moving may have made her feel less secure, too. She'll adjust, but it could take a while.
I think we've all learned that we have to bow to our Quakers' quirks -- you might have to give up nail polish, for example.

We can't wear red shirts -- I wear mine to work and change when I get home. I can't wear jewelry at home anymore. Or clothes with decorations like embroidery or sparkly bits. Anything like that can upset a Quaker and make them bite you and I don't think it's an attack; I think what they're doing is trying to remove the offending thing because they see it as a blemish or a bug and it's their job to keep your personal hygiene nice and spiffy.