First, Mreow said it was her mother's decision to try and let the neighbou take a kitten, sometimes you get overruled by older family members. Second, at four weeks kittens are still suckling and SHOULD NOT be taken from their mom. Here in Canada there are laws preventing puppies being taken too early, maybe the same laws apply to cats and you can use those to back you up? Wait another six weeks. Mom will be starting to get tired of her kittens and spend more and more time away. 12 weeks is when cats should be given away, and mom will most likely not protest.
It is going to take time to win back your cat's trust. When the kittens are this young, too many visitors can make Mama extra protective. If one leaves with a visitor, she will be extremely protective. Don't push her, you don't want anyone to get hurt. Once she gets over feeling the need to protect kittens she will SLOWLY back to being her old friendly self. ( taking the kittens away early will not speed this process up and may make it take even longer to get back to her old friendly self.)
Dr. Seuss~DLH (brother's cat)~June 2007-
Misty~DSH (my cat & Mooby's mom)-?- Sept. 15, 2014
MooBoots(Mooby) ~ DMH(Mom's cat)~July 21, 2008-
Sunshine~ Golden retriever X white german sheperd (Dad's dog)~October 24, 2008-