Life insurance is available to anyone, but the rates change according t the risk of the life insurance applicant. Insurance companies will ask you a series of questions regarding how much and how often you drink, and may also request tests as part of the general application process that include testing your blood for signs of excessive drinking. You can be denied coverage for a DUI, but a single occurrence several years ago is not likely to pose a serious problem.
As a general rule, a DWI 5 or more years ago will probably not have much effect, but the insurance company may use it as part of a more comprehensive analysis of your behavior. Having a glass of wine with dinner, for example, is not generally a problem, but it may also be a possible sign of risky drinking behavior. Additionally, a DUI in which injuries resulted increases your health risk, and having such an incident within a 5 year period will almost certainly result in much higher rates from some companies, or complete denial of insurance by others.
On the other hand, cash value life insurance policies are available that do not require any health examinations. These policies tend to offer fewer benefits, and may be limited to term life insurance, negating much of the usefulness of the policy during your lifetime. Life insurance is available for everyone, but the cost of purchasing the insurance may be prohibitive for people who drink heavily. If you simply made a mistake after a holiday party a few years ago, it won't be an issue, but if you drink heavily often insurance is likely to be expensive.