The Prophet Passed Away on Monday

The Shadi al-Ahuwan allows for all of this. The one that is the least encouraged is to specify your son. This does not invalidate the Caliphate as some extreme people say. But it is not ideal, and it is definitely not the best. And so Allah allowed the last of the Sahaba who was the Khadifa to open this door. To indicate that it's not invalid if there is a dynasty.