Welcome to the forum Mohammed.
Your fig tree should be able to survive outdoor temperatures in your area. Yes temps as high as 50+ c is very hot but it should survive with proper acclimation and care. I've experienced heat as high as 122F only once in my life in Death valley in the US (highest recorded temp was 134f = 56.6c). That was too much for a pale one like myself. I honestly thought my time had come. So, I know that kind of heat is very intense and can potentially lead to death for us humans if we don't constantly drink water when exposed in that environment.
So, the main concern for your fig tree in the hot, dry, season will be water. If you are able to collect rain water at all, that would be a big plus for you. Especially if your main water source is from desalination plant as Francisco mentioned. Letting chlorinated tap water sit in an open bucket for 24 hrs or so will remove most of the chlorine since chlorine will evaporate in to a gas. De-chlorinated water would be less stressful on your tree.
If you have difficulty accessing commercial fertilizers, one of your best sources of natural organic material may be chicken manure or similar - just as Francisco indicated. Just use caution especially with chicken manure. If it is un-composted, it can burn your plants just like commercial fertilizers. So use it sparingly unless you have access to well composted manure. Even then, be careful not to over-do it.
Hope this helps.
May you have many delicious figs :~) .