Sorry about this Pawit.
My brother always told me that the phone was rebooting randomly.
After this talk with you. I asked this, and now he says that it wasn't really rebooting....
It's turning off (without any reboot).
Considering this....Can we assume that the problem is the battery?
The strange thing is that is totally random.....some days (or some weeks) goes well. And some other days goes off.
The Battery brand is Polarcell and i have many more Polarcell batteries in other phones working well.
I'd say go back to stock ROM, if it's still happening, it's a hardware problem. It maybe a battery problem or other hardware problems.