What could be causing my dad's vertigo?

My dad started getting vertigo (no other symptoms) a couple of years ago. They did a battery of tests on him and couldn't find an issue and told him it was just a part of getting older (what a load of crap!). Anyway, my mom and I think he needs to see a neurologist, to make sure there is nothing going on in his brain.

Off the top of your head Uny, can you think of any conditions associated with vertigo? My dad had prostate cancer and removal about 10 or so years ago and has been cancer free since. He also had basal cell carcinoma on his nose some years back and has not had a reoccurance. He is around 73 and in overall good health. He still works full time as a lawyer. Thoughts? Thanks.