(child exerted undue influence on her mother by convincing the mother to leave the other eight siblings one dollar each under the terms of the mother's will while will left everything to the one child; child had confidential relationship with mother who relied on child for meals, housekeeping and transportation and child controlled mother's bank account and was agent under POA; at time of will execution, mother had suffered a stroke that affected her memory and thinking abilities; child kept dealings with mother secret from other siblings).