Alcoholism Recovery & Treatment

My friend recently “fell off the wagon.” Tonight we went out to dinner and I could smell the booze on his breath, and noticed the frequent trips to the men’s room. Since I’ve been very supportive of his sobriety over the past year, how do I tell him that I realize he’s drinking again and not to involve me unless he want’s my help? I feel like a fairweather friend and like I’m kicking him while he’s down. Like most questions, I probably already know this answer but I’m having trouble accepting it. Your experience is greatly appreciated.
He had been attending regular, weekly AA meetings and was in rehab for 28 days in early Spring. Thanks for the advice.