Your friend should pick up some holistic dog books to get an 8 week allergy diet. Dr. Pitcairn's book has some wonderful recipes in it.
For my Newf Cassie, I found she was able to tolerate Holistic Blend - Lamb, California Natural - Lamb. I also add essential fatty acids to her diet daily- sardines, salmon, flax seeds crushed/oil, hemp oil, borage oil or Evening primrose seed oil and there are many other good sources of essential fatty acids.
I use astragalus to build the immune system. I also give her dandelion root to improve liver efficiency.