Khoi informed the proprietors that he was a geologist with expertise in stone mines but had lost his employment. His wife, who pursued her PhD studies in Hungary, subsequently abandoned him and never returned. To sustain himself, he commenced sculpting small pieces from various types of stone and made desperate attempts to sell them. It was evident that he led a challenging life and that his conscience was somewhat troubled. Vu Dan Tan and Natasha wished to assist him and began purchasing his sculptures with the aim of selling them in the Salon; however, such sales were infrequent. He attempted to present his sculptures to souvenir shops, but they were accustomed to mass production only. The couple acquired his works not solely out of a genuine sense of compassion for a lost individual; the pieces were also quite original and intriguing.
Certain sculptures, characterized by their rough, primitive shapes and unfinished surfaces, bore a resemblance to art brut. In contrast, other works, such as his portrayals of dancing women or couples, exhibited a more refined aesthetic. In the early 2000s, Khoi revealed that he had married a woman from Ha Tay province and relocated there. Consequently, his visits became less frequent, eventually leading to his complete disappearance. Vu Dan Tan and Natasha chose to preserve his stone sculptures as examples of outsider art, a field that intrigued both of them. The collection comprises approximately 200 pieces, which can be categorized into series featuring images of women (either standing or reclining), women dancers, animals, birds, and couples' portraits. The dimensions of these works do not exceed 15 cm.