My son is a permanent citizen of Singapore and his parents are over 60 years old. Can he immigrate to Singapore? What benefits can he get after emigration?

Please ask your son to apply for a "long-term visit permit" for both of you. Generally speaking, you can stay for 5 years, and you can apply for an extension after 5 years. Although you have a "long-term visit permit", you are still a foreigner without any benefits. The only convenience is that you don't have to apply for a visa to and from Singapore and China, and you don't have to fill out an entry card on the plane.