I had a similar problem with my husband. In fact one time he did accidentally switch off the freezer by mistake, thinking he had switched off the kettle - fortunately we saved most of the items simply by cooking them and refreezing.
My stopgap measure at the time was to place a large, thin plastic chopping mat in front of the fridge/freezer sockets and hold it in place with strategically placed items on the worktop.
It solved the problem immediately (out of sight and out of mind) and my stopgap measure actually became the permanent solution.
When a similar problem occurred with my husband turning off the toaster at the wall, making it impossible for him to make a slice of toast when he fancied it, I used another thin plastic chopping mat to disguise that socket too, and again it worked.
The plastic mats are still in place but we don't really need them these days as, earlier this year, my husband lost the ability to make tea and toast and now seldom ventures into the kitchen other than to wash and dry up these days.
It's a different situation I know, because we have a full house here with people in and out all the time, so my husband is never alone these days. I don't know how successful my solution would be if my husband was still able to be left alone and free to move things around the kitchen as he wished.
Kevin is right though, switching things on and off is going to be a problem, so as a longer term solution the change of sockets is likely to be a good way forward.
If I'd had different sockets maybe I wouldn't have wasted money and time trying to fix our porch light over a whole weekend (before eventually realising that it had been turned off by a long forgotten internal switch about 7ft high up on the wall) - nor would I have had the embarrassment of calling someone out to fix the central heating boiler when it suddenly stopped working, only to find that it too had been turned off at the socket!