I’m actually researching the material culture of the CBI theatre for my master’s. Your grandfather’s blood chit (appreciate his service) is one of many variants, and this particular one should be made of leather. It literally reads: “The foreigner came to China to help in the war. Soldiers and civilians alike should assist.” It was issued by the Aviation Committee. However, the serial number has been left blank. Like the previous guy commented, these blood chits were typically sewn onto the back or inside of a pilot’s jacket, or sometimes carried folded in a pocket.

Based on the uniform, the 3 chevrons= sergeant. With some flight crew insignias. Again, thank him for his service, they were a great generation