He's the way he is because he's a drug addict that struggles with addiction. That's why his father thinks he is weak and has major reservations about handing over a billion dollar company to him. As well as the fact his father is power hungry and doesn't want to cede the throne.
I like a lot of the dialogue about the media industry as well. The father wanting the old/reliable distressed local tv network assets but the son seeing the changing media landscape wanting to branch into digital more. It's a lot like another HBO show "Silicon Valley" in that the industry dialogue on the show is actually topical.
The weakest character on the show is the black sheep nephew, just seems kinda useless.
Ronan is Kieran Culkin, Macaulay Culkin's real life brother fwiw. Gotta be depressing you're typecast forever as Home Alone and your brother is in the hit show of the summer. Although he is rich as fuck still.