Yep, old academics are employed to teach at universities in developed countries. Plenty universities back home, both redbrick and prestigious. Good luck!

Ivor Etherington was one of my maths lecturers back home during the academic year of 1971-1972 at my key university. He lectured me in algebra. He was born in 1908. He was slight in build; he used to finish a lecture in the middle of a sentence, and resume next time from that point on! He looked older than 63, but he continued working for the university until 1974, after which he enjoyed 20 years of retirement. He had a brilliant mind.

https://en.wikipedia.org/wiki/Ivor_Etherington

RE dual nationality in China, unavailable at present, but you never know what the future will bring! We can live in hope!