Extend S2 visa

My son is South african. His wife is Peruvian. His wife also has Italian residence. They married in China last year. They both have been in China since 2014. Their visa expired in february 2020 and had their visa extended in china. With the special situation around the world with covid 19 they need to stay in china longer. They were issued 1 month S2 visa but need to extend again. Is this possible because the extry exit in wuxi refuses