Pharmaceutical grade is going to be manufactured at a higher level of quality than ordinary fish oils. It's a fairly new product but more and more companies are adding a line. I've used both and IMHO you're getting more than the difference in what you pay for with a pharmaceutical grade. Everyone's different, though, maybe your dad has a sample size you can test out for him.
I like Health From The Sun also. They do a good job of hitting up the entire spectrum.
I like Health From The Sun also. They do a good job of hitting up the entire spectrum.