With 5ft seas, opposing wind and current many people would have some difficulty at the surface and getting back onto the dive boat.
If I were diving with novice divers I would probably abort the dive and look for calmer seas.
If the seas are that rough, and if you choose to dive in those conditions, then it is best to spend as little time on the surface as possible. At the beginning of the dive you might want to descent immediately upon entering the water. As far as recovery at the end of the dive, well that’s where it can get tricky.
The boat should have a tag/float line trailing it. Divers need to wait on that line until it is their turn to get back on the boat. Very important to stay back from the boarding ladder until it is your turn to board. In rough weather it is not uncommon for divers on the ladder to fall off. You don’t want to get hit by a falling diver.
Also, remember that when you are on the boarding ladder, keep your mask and regulator or snorkel in place until you are onboard and secure as the likelihood of falling is even greater in rough seas.
In my opinion… it may have been proper for the dive boat captain to abort the dive, if he saw that the sea conditions were going to be beyond the skill level of any of the divers. But I was not there and I don’t know what the skill levels of the divers were. That’s just my opinion.
In any event… it is ultimately up to each diver to determine if the conditions are beyond his/her abilities. It is “part of the dive plan that each diver & buddy team observes and considers the conditions prior to making the dive”.
I use the 10 second rule when considering the conditions at the dive site. If conditions are such that it takes me more than 10 seconds to decide whether to make the dive….Then I Don’t Dive….