When my dad had a stroke of that type, his greatest frustration was his inability to speak. These days, there are a number of aps, some of them free, that have drawings keyed to a voice. You press the button with the picture of a hand, and the ap says “HI”, etc. Some also have recording ability so you can have somebody put some choice expressions on some of the buttons.
Mom is still talking up a storm. I love that tech helped your dad. My dad lost his ability to speak quite early in his Alzheimer’s. I have no idea if that app would have been useful to him at the start so he could have said what he wanted.