Are gay men more prone to alcoholism, especially as they age?
Here we have another issue that depends greatly on the individual. First there is a difference between actual "alcoholism" -- an honest-to-goodness addiction to alcohol -- and heavy drinking that may be caused by, in part, [temporary] problems in a person's life. This remains true regardless of the sex of the individual or their sexual orientation.
It has always been true that some people turn to alcohol in times of great stress, as the "buzz" or more that they get from drinking can help them temporarily forget their problems and feel good for a time. This should not necessarily be confused with true alcoholism, an insidious and progressive disease that has nothing to do with an individual's problems or the stress in their life, although it may be exacerbated by same.
A lot has been written about the aging gay man, who is alone (especially if a partner has died), and who may be afraid he is losing his attractiveness and the ability to attract a partner for sex and romance. I dare say this has more to do with growing older than it has to do with being gay. Straight men also suffer the same insecurities, the fear of loss of virility and the ability to attract women, as they grow older. Some men age well; some men do not. How a man deals with getting older often depends on other factors in his life such as his health, financial stability, number of friends and so on, none of which have much to do with sexual orientation.
Because of the isolation that some older gay men feel [and undoubtedly straight men as well, particularly if they are divorced, single or widowers] there are those who insist that aging gay men are more prone to alcoholism, but the truth is much more complex.
There are those in the gay community, as well as the straight, who turn to alcohol for solace (which, as noted, is not the same as genuine alcoholism) and those who don't. There is no indication that there are more alcoholics in the gay male community than in any other segment of the population.