Your father most likely has
dry eye syndrome. Mine lead to corneal erosion. There is an explosion of research now on Lactoferrin for many purposes: ulcers, gastrointestinal flora balance, antibacterial, anti-inflammatory, osteoporosis, autoimmune disorders such as arthritis, dry eye syndrome, et al.
Here is a url that might interest you re dry eye syndrome:
http://abstracts.iovs.org/cgi/content/abstract/46/5/2046
This particular study used 270 mg per day.