Johnny may have abandoned/disowned Robby, But He Redeemed himself by Becoming Mr Diaz x Lawrence.
Hear me out an maybe explain your idea on this, but from what i've seen from the writers. Johnny may have disowned Robby and became Miguel step-dad, impregnating/Marrying Carmen, and becoming the Husband/Stepdad of the Diaz family, but Robby is Johhnys former son, and he is only invited to Johnny/Carmens house as a guest and not as Family. Like Johnny and Miguel go on Karate adventures, and Robby is just a tag along, 3rd wheel, lost puppy who follows who isn't his dad no more. From what I've seen is that Robby is just a houseguest and not a Diaz Family member (Even though his Dad is now Mr Diaz) And He should just try get a life of his own and not try to stick to a Father-son duo as like a 3rd wheel, lost puppy. according to my observations for S6. Any thoughts and opinions ?