That doesn't really surprise me. A, D, and E are oil-based vitamins and don't survive storage in our dry feeds well, especially crumbles with their high surface-to-air ratio.
For E, yes - you can use regular human vitamins. If I were you, I'd talk to him about wheat germ oil as it contains A, D, and E. Though it looks like he's thinking you need more E?
You can use regular oil vitamin E capsules though. I'd ask him what dosage he recommends.
If you choose wheat germ oil, you can use a spray bottle and literally spritz it on food if you use a little food. Of you can mix it into the feed before feeding. I used to use about one ounce per gallon of feed, mixing it in well. You really have to stir and stir the oils.
