To be honest, that doesn´t sound very good to me...
(normalising after forging would be good after serious forging action, as mentioned before)
Again, bright red is not very self explaining to someone not used to the color range.
(820°C is as far as I have in mind the hardening temperature for the common spring steels, so bright red is good, the difficulty is to be exact without years of experience. Remember, under light, colors are different than in a darkened room. By the way, the complete prod must be even bright red for hardening, not just a part of it)
Did he mention on what temperature the flame of used oil burns (I bet the temperature of a oil flame is higher than 400°C)???
Did he mention how long tempering should be to reach the desired softness (I dont speak from hardness here, because tempering is used to reduce hardness from a hardened part and reregulate the structure to a certain point where it can be used)??
It is easy to say it is finished when it is gone, but depending on the form of the steel you can have a pan of burning and smoking motor oil for several hours. And I would suggest you got the temperature only on the surface where the burning reaction can process, not underneath.
The longer you temper, the softer the steel will get. The use of low temperatures for a long time can be swapped by higher temperatures for a short time and vice versa.
Oil can be a medium for tempering, that is not very extraordinary, but then exactly heated oil (with a bit of igniting danger) just to have a better regulation possibility compared to air in an oven.
So this method seems not to care about time and temperature.
One final point: do you have any idea what happens when you burn used motoroil? Besides smoke will be very toxic but the laws in the Netherlands(and the european union) are not joking about environmental criminal actions like these. This process could be very expensive.