Sorry to break it to you but your buddy is doing it wrong. For the following reasons:

1. 500 sol/s means he is over-volting / increasing power consumption. That is LESS profitable than undervolting because you spend so much energy for minuscule gains.
2. Temps do not need to be "around 70c" to get good profits. He/she is simply reducing the life span of his/her GPU.

These are "basic" knowledge when it comes to GPU mining and if you haven't done enough research to know this then "wtf are u doing."