Your dad's doc is wrong or a pimp of pfizer. One of my dads docs said 1200 mg twice a day, the others are so so. Get the high purity fish oil (sometimes called distilled fish oil) for him.recently my dad's doctor told him that he shouldn't be take fish oil, becasue of bad things in fish oil. I'm not sure about this, but I take it everyday because of joint issues, but every morning during the week I put flax seed oil in my shakes.
I read a few months ago that flax seed oil doesn't have the same benefits as fish oil.