I have done some research and it turns that the father overt incest and mother covert incest combination was actually researched back in the 1950s and 1960s. Here is an excerpt from Incest: A Psychological Study Of Causes and Effects With Treatment Recommendations by Dr. Karin Meiselmann published in 1978:
Kaufman, Peck, and Tagiuri (1954) did the first in-depth clinical study of mothers and daughters in incestuous families. Although their sample was very small, their description of the dynamics of the mother-daughter relationship has been quoted frequently in the incest literature and deserves our special attention here. Essentially, their formulation states that the mother develops a very special, conflict-laden relationship with one of her daughters long before incest occurs. The chosen daughter is initially treated very well, even being overindulged in comparison with her siblings, and she is encouraged to assume the responsibilities of an adult woman very early in life. At first, mother and daughter are allies and workmates in the care of younger siblings and the performance of household tasks, but gradually the mother relinquishes her responsibilities to the daughter and allows her to play the role of "little mother" in the family. This role reversal implies a special, wifelike relationship with her father. Although encouragement of incest is not on a conscious level, the mother is assumed to have backed out of her sexual role in the marriage and been relieved when her husband directed his sexual attention to the daughter.
Having succeeded in setting up the daughter as "little mother," the mother gradually becomes dependent on her in a childlike fashion and begins to displace her feelings for her own mother (the daughter's maternal grandmother) onto her daughter. The quality of the relationship then changes, with the mother expressing hostility to the daughter in direct and indirect ways while still remaining dependent on her. At the end of the preincest process, therefore, the daughter has been thrust into a premature adult role, rejected by her formerly loving mother, and somehow expected to be responsible for the needs of other family members.
The incest scenario proposed by Kaufman and his colleagues (1954) has been repeatedly found in subsequent clinical studies of father-daughter incest (for example, Heims and Kaufman, 1963; Rhinehart, 1961; Machotka, Pittman, and Flomenhaft, 1967). Lustig and others (1966, p. 34) claimed to have found this mother-daughter pattern in all of the six families studied by them. "In all cases [the daughters] had become the female authority in the household by the age of eight. Their advice was sought by the mothers on topics from groceries to sex. In addition to this, the daughters had much more responsibility for the care of the house than would normally be expected." They also described cases in which the daughter's responsibilities included acting as an intermediary between her parents when martial conflicts arose. And finally the case history descriptions from abroad often contain the same pattern of dynamics within the incestuous families. For instance, Magal and Winnick (1968, p. 181), reporting on an Israeli family, observed that the mother "was a woman of weak character who lived in permanent fear of her drunkard husband. Ever since [the daughter] was a little girl, her mother preferred her to all other children and put her to various tasks...[The daughter] used to go marketing, she managed the money, took care of the smaller children. When she was twelve years old, [she] has to take care of the household and she alone could calm down her drunk father by talking to him kindly. She induced him to go to bed and sat by him all night."