I really don't think it matters what you present. My (limited) experience in buddy selection was people would chat and choose. Most boat diving I have done has been group diving in which everyone is solo as no one has accepted the role to be a specific person's buddy. However, that role has limited responsibility. If in the situation described a buddy just drops like a rock into the abyss, no one should risk their own health in that scenario. Let the staff handle that.
I think dive guides watch people during the dive and adjust accordingly. Who can they safely monitor very little to whom do they need to monitor more. Unless they are brand new, dive guides see a lot of people fairly quickly.
As far as the side conversation going involving
@Dody and his wife, I doubt he has shared all details necessary for a clear picture, and people have a tendency to interpret statements through their own lens. I'm sure we've seen the overbearing husband on a boat, and a number of folks here may be interepreting
@Dody as such. As I have never seen him and his wife dive, I won't say this is similar to what I've seen, but I won't say it isn't either. I just won't throw stones here.
Stress is a significant issue for some people (one of my most nervous students for diving in the Puget Sound was a 6'5" 280 lb firefighter) that needs to be addressed in training. It happens and not addressing stress but ramming through combined with "you'll be fine" is counterproductive for learning.
@Dody has agreed that more training for his wife is a good idea, so he definitely isn't being hardheaded/stubborn. Everyone knows I'll recommend fundies here, but since that's a given, I'll keep my mouth shut
.