OK, then, I will.
As I said, the problem was that you did not seem to accept just what a parlous state your electrics are in. Or at least the parts you've shown us; yes, it's possible that the rest is fine, but I wouldn't bet much on that.
If you're willing to learn, wrt this, then what you need to learn is how to rewire an entire house from scratch, because that is what may need to be done. And you do not have time to learn all that you would need to know - you cannot put off getting the work done.
That's probably premature.
You cannot do anything with the existing wiring you have shown us. You cannot extend it, you cannot replace any accessories or lights, you cannot even touch it until you are at the point, with new reels of cable, tools for chasing walls and ceilings, capping/conduit as appropriate if you want or need those, etc to hand. And the same may well go for the rest of the installation.
You have seen how those cables are snapping, and the insulation is just crumbling away - for all you know every single bit of wire in your house is like that. Just taking off switches or sockets to have a look could cause catastrophic failure of the wiring so that you're then in a house with no power until the rewire is finished.
The lighting circuit that that room is on should be left switched off, and preparations for a total rewire put into place, with all tools and materials acquired, before you do anything to any other part of any of the other circuits. Maybe you won't need to rip everything out, but you could so easily and quickly pass the point of no return that it would be very imprudent to not be able to start ripping everything out and replacing it the moment you decide to see what state the rest is in.