How to best quick fix worn out tyre I want to share my experience and ask for some further question on this issue.
I was on a roadtrip as I found out that tyre on my rear wheel was worn out. I could clearly see the threading (if this is correct name for that) on the side walls of the tyre near the rim. I swapped front and rear tyre to have the weak one in front because it gets less pressure. Was this correct thing to do? Also, should I have deflated the air pressure in tube when I saw this?
After some time, the tube punctured. As I examined it, the whole one side of the tube was worn out because the threading of the tyre rubbed against it. So there was a full circle of worn out material. Therefor, I didn't want to patch the tube because it seemed like it was already too weak.
What I did was cut that tube entirely open, wrapped it around new tube, stick it in place with some ducktape, and then put that tube inside a tyre. That way, the tyre could only rub on the outer tube, deform it, and perhaps even puncture it again, but the hole would have been too small to let the tyre reach the inner tube, and it seemed like pretty smart fix. What do you think about that?
Unfortunately, after some time, the tyre got so worn out that the threading start to break and a hole was made in the side wall. So, the tubes popped out of the tyre completely in form of a little ballon. At that point I had to stop and seek for new tyre.
But, I was in remote area and there were no bike shops, so I got some old tyre from some random guy that was also kind of worn out. It was worn out on the top wall (if that is the name of the part of the tyre where it touches the ground), but not as much as my old one. I put his tyre and it almost got me to a place where I could buy a proper new tyre when again the tube popped out in form of a ballon.
Then, I deflated the tube almost completely and walked the bicycle to the bike shop. Should and could I have put both my old and his old tyre to prevent leak of the tube? It seemed like a good idea, especially because they were damaged at different places, but I didn't want to risk some other stupid thing that might have happened. If that would have been a good idea, what about if the tyres were damaged at the same spot? Would then make sense having both of them? Two tyres and two tubes does sound ridiculous but in the means of necessity a lot of things cross my mind.
Also, I appreciate any other guidance on what to do in similar situation, or any sharing of your own personal experience.

Later:
Boot is something I wasn't aware that could be done and it sounds like a smart fix for a hole in the tyre. In my case, the threading of the tyre was damaged on the whole circumference of the sidewall, not from debris as Weiwen has assumed, just from being worn out. In that light, I think that old tube wrapped around new tube was better solution since there was no hole in the beginning. Of course, once the hole was made in a part of sidewall, I should have made a boot.
For some comments: I know I should have checked everything beforehand. I didn't. I hope this discussion will help someone other who gets into similar situation. Whether because he was stupid like me and didn't prepare, or did prepare but some bastard stole his panniers with equipment :-)
There are several questions here.
You were on a road trip and found a hole in your tire...

I swapped front and rear tyre to have the weak one in front because it gets less pressure. Was this correct thing to do? Also, should I have deflated the air pressure in tube when I saw this?

And...

Should and could I have put both my old and his old tyre to prevent leak of the tube? It seemed like a good idea, especially because they were damaged at different places, but I didn't want to risk some other stupid thing that might have happened. If that would have been a good idea, what about if the tyres were damaged at the same spot? Would then make sense having both of them?

To summarize:
You found yourself in a bad situation and improvised several amazing solutions using what you had on hand to get a little further down the road until you had no choice but to walk.
Your solutions were the best you could do in the situation.
Suggestions:
Do an equipment check and solve problems before you start your road trip. Identifying marginal tires, brake pads, etc. and doing basic maintenance before you start on a trip will reduce (not eliminate) issues on the road.
What your bring in the way of spares and tools depends on how long your trip is.
You brought a spare tube and the tools to install and inflate it - which is excellent. On your next trip consider bringing a spare tire. As a rule of thumb its nice to have a spare tire if you are going to be riding further from home than you want to walk back. Even if your tire is new they can be damaged while riding in a way that requires replacement.