Consular officers decide on the visa's period of validity, duration of stay and number of entry in the light of China's laws and regulations. The visa officer feel that your friend can only get the 3 months tourist visa. He can travel to HK to apply for a new China visa, then re-enter China, it is also possible for him to apply for extension of stay duration at the local Public Security Bureau.

yes, it is possible for you to renew your business visa in China, you should submit all required documents for business visa application, in fact, you will issued a new business visa in China.