Here is a comparison from one of the drug types website, bear in mind these are long term effects
ALCOHOL
What are its long-term effects?
Prolonged, heavy use of alcohol can lead to addiction (alcoholism). Sudden cessation of long term, extensive alcohol intake is likely to produce withdrawal symptoms, including severe anxiety, tremors, hallucinations and convulsions. Long-term effects of consuming large quantities of alcohol, especially when combined with poor nutrition, can lead to permanent damage to vital organs such as the brain and liver. In addition, mothers who drink alcohol during pregnancy may give birth to infants with fetal alcohol syndrome. These infants may suffer from mental retardation and other irreversible physical abnormalities. In addition, research indicates that children of alcoholic parents are at greater risk than other children of becoming alcoholics.
Think you know the facts about alcohol abuse? If you consume alcoholic beverages, it’s important to know whether your drinking patterns are safe, risky or harmful.
WEED (Marijuana)
What are its long-term effects?
Marijuana smoke contains some of the same cancer-causing compounds as tobacco, sometimes in higher concentrations. Studies show that someone who smokes five joints per week may be taking in as many cancer-causing chemicals as someone who smokes a full pack of cigarettes every day.
Ecstasy
What are its long-term effects?
Repeated use of Ecstasy ultimately may damage the cells that produce serotonin, which has an important role in the regulation of mood, appetite, pain, learning and memory. There already is research suggesting Ecstasy use can disrupt or interfere with memory.
Cocaine
What are its long-term effects?
High doses of cocaine and/or prolonged use can trigger paranoia. Smoking crack cocaine can produce a particularly aggressive paranoid behavior in users. When addicted individuals stop using cocaine, they often become depressed. Prolonged cocaine snorting can result in ulceration of the mucous membrane of the nose.
Heroin
What are its long-term effects?
Long-term effects of heroin appear after repeated use for some period of time. Chronic users may develop collapsed veins, infection of the heart lining and valves, abscesses, cellulites, and liver disease. Pulmonary complications, including various types of pneumonia, may result from the poor health condition of the abuser, as well as from heroin’s depressing effects on respiration. In addition to the effects of the drug itself, street heroin may have additives that do not really dissolve and result in clogging the blood vessels that lead to the lungs, liver, kidneys, or brain. This can cause infection or even death of small patches of cells in vital organs. With regular heroin use, tolerance develops. This means the abuser must use more heroin to achieve the same intensity or effect.
As higher doses are used over time, physical dependence and addiction develop. With physical dependence, the body has adapted to the presence of the drug and withdrawal symptoms may occur if use is reduced or stopped. Withdrawal, which in regular abusers may occur as early as a few hours after the last administration, produces drug craving, restlessness, muscle and bone pain, insomnia, diarrhea and vomiting, cold flashes with goose bumps (“cold turkey”

, kicking movements (“kicking the habit”

, and other symptoms. Major withdrawal symptoms peak between 48 and 72 hours after the last does and subside after about a week. Sudden withdrawal by heavily dependent users who are in poor health can be fatal.
Just goes to show that Booze is up there with the worst and would easily be a Class A if released today.
As for the admitting he went boozing vs taking coke. That is down to conditioning and social acceptance rather than damage caused. Most have abused alcohol so see it as OK. Plus 99% would not admit hard drug use to their parents due to the reaction it would get, instead getting their knowledge from "the streets" rather than someone with knowledge