He applies the thermal grease with a screwdriver though. I never recommend apply TIM that way because you can scratch the surface of the die, but this should give you an idea of how to do it.
Yes you can, you would need to find somewhere to buy the exact same CPU though except in i5 or i7 to make sure it will fit your laptop. Can't guarantee it will work 100% though but it's worth the try.
He applies the thermal grease with a screwdriver though. I never recommend apply TIM that way because you can scratch the surface of the die, but this should give you an idea of how to do it.