Those three would work together. The limitations they do have don't affect them while they're sailing. A quadriplegic gets strapped into a chair, but the other two guys on board could do the things that he can't. In the 2.4mRs, they figure out how to manage their lines, even if they have one hand. A quadriplegic can wrap lines and use their teeth and anything else.
Quadriplegics actually use swimming a lot of times as an exercise.
Besides, they'll float, because all sailors wear life jackets all the time. And with the fixed keels, the boats might tip over, but they won't stay over. It's what's called a knockdown, not a capsize. That happened to our Sonar crew the other day. Their boat was hit by about a 30-knot gust that knocked the boat over.