He has a long-term history of excessive drinking and is now in his 60s. He is functional though, holding down a job and relationships with the family, which means that as a family we have up until recently brushed his drinking under the carpet and were unwilling to confront it to keep the peace.
After family involvement out of concern a year or so ago, he voluntarily and supposedly "gave up" drinking spirits completely and only drank the occasional beer or wine publicly.
Fast forward to today, all he drinks publicly is non or low alcohol beer.
The issue is he has a bottle of vodka hidden in his car and has been regularly spotted nipping from it especially first thing in the morning (6-7am 
). This behaviour is much more noticeable to us as he is currently living with us short term. We have confronted him and initially he denies it but then admits but is defensive, using all the excuses and reasons you can imagine. He says he has contacted AA but doing it online won't work for him.
His health is poor, his stress management terrible and we are very concerned and want to support him to give it up but do not know how. It is not helped by the fact that his first reaction is to deny and lie. He has a non supportive partner who has alcohol dependency herself so we have not brought this up with her.
I am having problems with my DH who is furious with the family member, and says he has lost all respect for someone who needs the bottle at 6am in the morning.
Is there anything I can do? Any support I can guide him to?
The secret drinking concerns me, when I discussed it with him I said I would feel more comfortable if he had a glass of wine instead with us instead of doing it sneakily.