Ok, the word "crippled" needs to be removed from vocabulary....
It may be more appropriate to say disabled but not everyone who is disabled is visually so.
Basil321; might I suggest that your nephew seek a second opinion. And if his dx is still the same that he will be unable to walk then the best thing to do is to accept it as such. Also you did not mention what disease your nephew has.
XtormentedchikX; Not everyone who has a disability, whether it be blindness, paralyzed, missing limb(s), disease, etc... Does NOT want pity but wants to be treated like a person and to be accepted as they are.
I have been given a disability of 30% however if you saw me you would not see it (most of the time) as my disability can be felt by me and when it is acting up, others may see or sense it but I do not want nor need pity.
Instead of feeling sorry for us...why not reseach the disease and empower yourself...
Look beyond the disability and get to know the person.