Boss,

You had one month time and it is suprised to note that you have kept such a important work pending for last minute?????

Anyway for visa extension, medical test is must and pl.rush your family to medical commision(tomorrow morning )and complete medical tes.

They will take 3-4 days to give result and you have to physically collect that result and go to immigaraton office where they will take 1-2 hours to extend the visit visa

All the best and take care in future