Wheel chair ma manche Lina Plane Mai janchan ki afule jharera bhannu parcha ? Long transit ma wheel chair Mai basnu parcha ki k cha ? Yeso information paau na hai .

I don't know much about whell chair option but there will be some Nepalese traveling on the same time who would be helpful. I had once helped a nepali mother while I was on my way to the US.
Q) How to find the person? If you are booking the ticket through travel agency in Nepal, they can help you get connected with other Nepali travellers.

What is the arrival city in US? 

Yes I was looking for someone who is traveling through same route but couldnot find . She is coming on March 23 from ethiad airlines . Nepal to abudhabi to newyork to Dallas .

DId not match arriving city as well time.

If you talk to the airlines saying that she needs a wheel chair (Assistance), they will assist her during transit. Also, they will escort her to the plane and off the plane. They will take her to some rest area (spot) during the transit and also will pick her up once the flight time is up for check in.
wheel chair doesn't mean that they are sitting in that wheel chair in transit, they can find a comfortable couch, lounges in transit.
My mum went back to Nepal from LA through Singapore Airlines.
No Hassles