What's Happening discrepancy regarding Shirley, dad & sis

[Wawwie]

In a What's Happening episode where Shirley's sister is pregnant, the pregnant sister considers putting her baby up for adoption. Shirley reminds the sister that when their father DIED, their mother managed to raise all those children without a father.

Later, in What's Happening Now, there is an episode where Shirley's father is ALIVE. He is a truck driver who has always had a strained relationship with Shirley.