If your friend damages his rig or his battery due to misuse and lack of knowledge, I would blame you for recommending a battery chemistry without proper knowledge.
Lipo batteries are NOT for beginners unless they are willing to put in the time to learn about the chemistry, charging, discharging, storing, handling, etc. Know your electronics and how to use them with Lipo batteries. The rig he bought has a manual, read it. Axial has a website, surf it. The battery he purchased has paperwork with it - read that too. That way when things go wrong, you don't blame the company for a defective product.
For the record....The AE-2 comes preset with LVD on and Battery "MAH" rating equals "size of the fuel tank" and the "Voltage" equals "amount of horsepower"