This scenario takes place in the USA.
Suppose I have someone close to me who has a very serious drinking problem. This could be someone physically (living) close to me or someone emotionally close to me. For example, a sibling, an ex-spouse, a relative (cousin/aunt/uncle) living with me, my neighbor next door, or my co-worker or even my boss whom I have known for a very long time and the relationship is friendlier than a strict professional relationship.
This person drinks a lot. Sometimes they are sober but most days and most nights they are drunk. They also drive whenever they want to, regardless of their condition, regardless of others (including me) trying to stop them. This person is of age, has a valid license/insurance/etc. But I don't want them to endanger themselves and worse, I don't want them to take out a family of four in a horrendous car accident or disable an innocent person for life.
I understand that driving is a privilege and not a right. My question is, is there anything I can do so that the authorities investigate and revoke his privilege of driving a car? This person has never been caught driving drunk so far. And there is no way they are willing to give up alcohol or be counseled/treated. If yes, then which agency and how do I proceed? Is it as simple as just visiting my local DMV? Can I remain anonymous? What kind of consequences will it have for the person reported? Will it result in criminal charges or something? What kind of evidence will I have to provide or why would the authorities take my word pointing to someone claiming "he is drunk all the time so don't let him drive".
In case there are 50 different answers for this, I am interested in the state of California and New Mexico.