I am a huge fan of Adams irons. I currently play a set of musclebacks. That said, what your dad wants is going to be highly suspect on what kind of player he is.
The Adams A series is a club with a very, very, very wide base. I found that while that promotes a lot of forgiveness, it really prevents one from being able to take a proper divot. Therefore, I really don't like them, but I do have a full set of A4's at home if that's what he wants. However, they are the OS (offset) series, and I don't recommend offset clubs for anyone.
I am a personal HUGE fan of the Tight Lies club. I believe that they are the best game improvement club on the market (and I don't hold any stock in Adams, nor do I work for them). I gave my old set to my nephew, who is 12 and has finally outgrown his junior set. He hits them exceptionally well, and my guess is that he has a swing speed that is comparable to most 60 year olds. I believe that the shafts on them were medium. I don't know if they make a senior flex, but I know that the clubs tend to be quite inexpensive compared to others in the same category.