Is it permissible to transfer the father's body from his burial place in Kairouan to Tunis to make visiting him and maintaining his grave easier?

It is not permissible to move a deceased person after burial unless there is a necessity, such as being buried without a ritual bath (ghusl (definition)), or in usurped land or clothing, or if property fell into the grave, or if buried facing a direction other than the Qibla (definition). The matter mentioned is not among the necessities that permit relocation.