I just want to know after the 6 months is over for my family what next?

Hi Theodora, the validity is not the same as the allowed duration of stay. Usually, the duration of stay allowed by an L type is 30 days. After the 30 days over, you can try to apply for the S type at the local exit and entry administration department. If it can't be done, your husband and sons have to leave China and apply for the S type.