I wonder if part of Kenny’s challenge (I won’t call it a problem) with the situation is that he has been “the dad” for so long. He was the patriarch in his family. Now he is dealing with another patriarch. This one is from a different culture and is the head of the family Armando grew up in.
I wonder if he just isn’t used to not being the voice of authority? But Armando isn’t a child, and definitely not one of his. Kenny has got to get used to sharing the power or this isn’t going to last. Especially when you factor in Armando’s daughter. It is clear Kenny loves her, but he is also going to have to deal with Armando being the primary parent and decision maker with regard to her. I’m basing this on zero direct evidence, but given that Kenny has raised 4 daughters, I am sure he will have strong opinions on the raising of a daughter (just as he had strong opinions on Armando telling his family they were engaged rather than just introducing them and giving the family time to get to know Kenny - much as what usually happens in families meeting a significant other for the first time), rather than taking his cue from Armando.