As I believed that the fan I have ordered online won't arrive tomorrow I thought to repair my broken mini fan so that tomorrow I will something to use in case that it will get hot in the dialysis center. I had an idea to do which is to connect the same colored wires of the USB cable and the cable coming from the brushless motor.
With much difficulty stripping the tiny wires off because my hands now are like gelatin and have no strength in them, I did managed to do the job. I have made use of my nail clipper, our knife which is notoriously dull caused by my father's way of sharpening it, a tiny scissor, and a scotch tape.
So now there is no variable speed control, the motor is directly connected to the power source which is my powerbank. After reassembling the mini fan and connecting it again to my powerbank and turning it on, wow it worked! I am so happy that I have now fixed my tool for comfort and won't worry about getting a discomfort due to the heat.