I have a scene in my mind so picture with me:
Grace having a pebble in his class that doesn't have five legs, but 4. Rocky explains to him that the pebble had an accidet in which they lost one of their legs and they are having trouble to adapt.
Grace tries to cheer the pebble up by showing them that he also have 4 limbs, but the pebble says is not the same because Grace has always have 4 limbs.
The other pebbles also are not pretty sure how to interact with the pebble, because they have problem in their balance now and then and they just have a lot of slips and the pebble have started to isolated themselve to not pass for the embarrasment of falling in public.
One day Grace gets into the classroom, ready to speak about the disabilities that human can present and how they have adapt to live with them. The pebbles, always excited to learn about alien anatomy and life style pay attention. Grace presents differente visible and invisible disabilities, he points to his glasses as a easy example and explains that he can't perceive light as well as humans should.
He points to the exit of the classroom of his side and calls for someone to come in and another human comes in. The pebble with 4 legs gasps in shock when they see that the new human just has an arm.
Grace presents the new human as Simon, who had moved to the biodome some months ago and was adapting to Erid. Then he explains that they can made Simon some questions, if he feels comfortable answering them. The 4 legs pebbles make a lot of those questions and Simon answer all of them.
Simon shows how he is able to do the same things that Grace do in his own way, and also demonstrating that he having a single arm is stronger than Grace having two. The pebbles are impressed.
Simon gains a fan, and the pebble gains a role model.
Simon peacefully taking care of his plants the day before, when Grace came running to him and ask him if he has free time tomorrow to go to his class, because a little pebble is having a hard time by having just 4 limbs and Grace wants to show them that they are not alone.
Simon, who by this point has had time to adapt better to only having one arm and would want to see some friendly aliens besides the sassy rock and his mate, is like "heck yeah I have time".