It is NOT sterile. He MUST NOT inject it or he will almost be guaranteed to get an abscess or even worse.
Here is what he needs to do:
(1) obtain sterile vials, whatman syringe filters, syringes, pins, and some BA
(2) Add approximately 2% BA to the solution
(3) Filter the oil into the new sterile vials and filter it with the whatman filter
He should be fine is he does the aforementioned steps.
Cooking gear does not kill all bacteria. Some bacteria can live at high temperatures so I never, ever recommend just baking the gear to make it sterile. BA is what neutralizes the bacteria, it is not the heat.
Furthermore, it must be filtered. When gear has been tampered with foreign debris will be in the solution so it is absolutely necessary to re-filter the gear.