Call TG and ask to put WCHR or WCHS into the file key. WCHR means pax can climb stairs, WCHS cannot.

Your mother will be put in a wheel chair or onto an electric cart, depending on the airport and then be escorted from the check-in to the a/c door. P/up at BKK with wheelchair at the a/c door again, and taken care thru customs, immigration etc. etc. From the luggage carousel she will be brought curb side where you can meet her. If you are waiting in the meet and greet area, that's also fine.

Read my old post here. The circumstances are slightly different but you find lots of information here too.

http://www.flyertalk.com/forum/thai-...n-bangkok.html