Can S2 visa be issued in Nigeria?

Hello, I work in China ( residence permit ) and I am married to a Nigerian citizen. My husband has been getting his chinese visa, previously, in my country ( east africa ) but now the laws have changed and I am told he has to apply in Nigeria. My question is to know whether the chinese embassy issues S2 (I have been told that is what he needs by the PSB). He has been to PRC 4 times already. What would be the requirements as I cannot find any info about this type on the chinese embassy in Nigeria. Would there be an alternative visa he should apply for if they are not issued? Kindly advise.