hi WheninRome - congrats on your 2 years!
Regarding your cousin, it can be very hard to know from the outside appearances, how someone is doing on the inside. When I decided to quit drinking, I think most people on the outside would have thought I was doing great. Happily married, got a promotion in my job, we had just bought a house, took nice vacations. It was what was happening to me on the inside, that no one else could see, that made me quit.
Maybe your cousin doesn't have a problem, maybe he has a problem that will get worse later, or maybe he already has a problem but it isn't (yet) showing to the outside world. No way to know, really.
I look at my three siblings sometimes and wonder (all of them drink, often to excess). But I can't really know, so I leave it alone.