The probable connotation of the word “mind” in the excerpt is that the husband and the wife had a dependence on each other. That is why Obierika says that both –Ndulue and Ozoemena – had one mind.
Obierika continues saying that he remembers how, when he was younger there was a song that reminded them. Obierika thought that the husband was a strong man, not so dependant on his wife. So, when he used the phrase “the same mind”, he is stating that the husband’s weakness made him dependent on his woman.
The excerpt is part of the novel “Things Fall Apart”, written by the African author Chinua Achebe, published in 1958.