What is the best way to get a relative to voluntarily commit himself for a psychiatric evaluation?

A family member has had untreated/informally diagnosed psychiatric problems for years. He has wreaked havoc on himself, and his family, yet he has no idea of the problems he has been causing. An LCSW tentaively diagnosed him as borderline/narcissistic, obsessive-compulsive and he shows features of an uncommon eating disorder. He selectively chooses the people around whom he erratically behaves, so it's very hard to pinpoint when he will act out. Only when he's at home does he have manic episodes and cause chaos. He hasn't been physically threatening toward anyone, but his family members don't want to wait for him to be so, and they have had it with his quiet self-destruction and his meltdowns. What would be a successful way in which his family can get him to seek a psychiatric evaluation, then get him into treatment? His family is running out of options.