Generally, two unspayed females will not get along. They may be getting on now because the daughter is still young, and the mother is still feeling maternal, but as the younger female matures, she will get hormonal and it is most likely that they will begin to fight. I would recommend separating them (as long as the daughter is over 8 weeks) BEFORE they fight rather than after. They will not see each other as family, and as soon as the daughter matures, they will probably fight each other for territory.
It’s also generally advised to get female bunnies spayed because of the high incidences of uterine cancer in unspayed does. Obviously I understand your trepidation about your current vet – those statistics are not reassuring at all. It really is important to find a good rabbit vet for emergency situations though. A good vet should lose far less than 1% of healthy animals during a spay.