I'm assuming that's like pure alcohol (as alcohol related stats usually are to negate the difference in drinks), so if he only drank beer of around 5% he would have drank 8700 beers. Say he started drinking alcohol at the age of 16 that averages out to somewhere between 7 and 8 beers a week (or the wine/booze equivalent). While not exactly alcoholic levels, this is above average (depending on where he lived) and an unhealthy amount.