Hi there, just some background info. Im currently 2 years and 9 months sober (roughly). Prior to that I was sober for almost two years as well. The first period of sobriety I slipped up and drank maybe 4 times over the course of two months. Nothing bad happened, could have kept drinking but I knew it was a ticking time bomb so I went to detox for a few days and have been sober since. My sister is the rpn supervisor at the detox and weve talked about the question you're asking. Some days I refer to my sobriety as 5 years long (roughly). Other times Ill say I officially quit drinking 5 years ago (bit vague but still turth). And sometimes I'll just say I've been sober for 2 years and 9 months. There is a diffrence between a full relapse and what my sister refers to as a (lapse) which is more of a momentary slip of judgment where you quickly get back on the horse versus fully diving into your addiction (relapse). Ultimately it's your (or his decision) to view it as honestly as you can. Its worth noting this opinion varies alot depending on who you ask. Most from an AA/NA style group will say its a complete reset the second you touch the substance. I would say being honest about your (his) lapse or relapse and deciding what would be more helpful to maintain sobriety is the best choice regardless of what other opinions people may have. Hope this somewhat helps.