Well firstly I hope your family get through this safely. Always the first concern.
You mention armed guards on the gate. Are they reliable and trustworthy, and more to the point are they competent in skills and steady enough under pressure?
Its an awful situation to say the least. I think with my family I would be heading to the airport.
They had a very sleepless night last night as couidl hear the rioting and also smell the smoke from the fires. This morning no electric. They have food for about 3- 4 days and that is when they really start to worry as all supermarkets in the area have been stripped bare.
Also no fuel as tankers cannot get through. They cannot walk to the nearest supermarket even if it did have stock. At the moment they do have enough fuel to get around as one of the vehicles was topped up for the daily commute of about 60 miles round trip.
Most South Africans over 40 served in the armed forces as it was mandatory until about 1996 so are quite competent with guns whether rifle or pistol. No one wants to use armed force as that may complicate things further, but you have a right to defend your family and home.
They live in a huge compound of about 200 stand alone homes with only the one gate. The fence surrounding the compound is electrified with razor wire on top. That has been in place since the compound was built many years ago.