At his age of 14:
400 IU natural vitamin E complex daily. Do not use synthetic E.
Vitamin C depends on his diet. If he gets plenty of C through citrus fruit and green vegetables, he shouldn't take more than 50 mg daily. If he doesn't eat enough fruit and vegetables, he can have 100 mg C daily.
Folic acid. 500-1000 mcg (.5-1 mg) daily.
Calicum/magnesium (always take both together) 500 mg/250 mg daily, along with vitamin D, at least 1000 IU. If tested low, high doses are required. For proper heart function, magnesium should always be taken with calcium. Taking calcium alone can upset the balance between the two minerals that control the heartbeat.
L-carnitine 500 mg daily.
I can't give you a dose for the oil as I have no experience with it. Follow the instructions on the bottle.
These are approximate dosages.