The pic above shows a North American NA16A trainer of the ChAF Academy at Kunming
The low-wing monoplane with the fixed spatted undercarriage is a French Dewoitine D510; 24 went to the ChAF and were intitally used by a French volunteer squadron (the 41st FS) at Yunnan-fu. The survivors were later used as advanced trainers by the 17th FS at Kunming
The twin-engined a/c with the nose lamps is a DC-2, undoubtedly of CNAC
The belly-landed monoplane is a Vultee V-11, used by the 14th Squadron, another Foreign Volunteer Squadron
The in-flight pic of a biplane #118(?) is a Douglas O2MC; 80+ went to China and saw extensive use against the Communists pre-war.

http://warbirdsforum.yuku.com/topic/433/before-1942#.TlnCJl2E7DM

Chinese Dewoitines (this comesa from the French mag 'Aero Journal' #22 had a long article on export D510s. Apparently 24 D510s were ordered by the ChAF in mid-1937, these arriving in Kunming in the Autumn. These were used to form the 41st FS (with volunteer French pilots) in early 1938. They saw very little combat, but when Kunming was bombed by G3Ms on 28th September 1938, 3 D510s intercepted, claiming one G3M. Three other D510s, fully-assembled, but not delivered to the 41st, were destroyed on the ground. There's a picture of one of these in the article and it's obviously the same a/c as the wrecked D510 included in your scans. So it looks as if Grandad might have been at Kunming at that time. The 41st was dissolved soon afterwards and the surviving D510s went to the Air Academy at Kunming; possibly this was where Grandad was pictured in the cockpit and in front of one?
The survivors later went to the 17th FS, at Kunming) where they saw little more combat and the very last few went to the 59th FS (at Chengtu) in 1940.
Incidentally the Chinese didn't like the D510 much; they considered it obsolete, slow, with poor lateral stability and to be difficult to pilot. The huge radiator was also very vulnerable to enemy fire and after a couple of bursts of fire the motor-cannon lost any accuracy. Bit of a dog, it seems!

The book mentioned above is a very good basic start to the air war over China in 1937-41. It has a pic of that Chinese-built improved I-15bis, tho' it's called an I-152 in the book. The correct name was the Chung 28-B.
There was also a big, thick hardback called 'Flight In China Air Space' which covered the subject in more detail.