Really you think a one armed or one leg person can successfully do a rescue? Loose a fin sometime as see how well you do in the water. I have no problem with anyone taking a class. but reality has to set in sometime to say your disability counters the effort possibly to the point of being useless depending on the limitation. This is a reality and not a PC matter.
And before you ask i will tell you. I would not refuse to dive with a disabled diver depending on the dive. I also would,,,, not with out question, expect them to be able to render any meaningful emergency assistance if needed.