What should I do concerning my certainty that my father drank intoxicants after smelling its odor in my storage room?

If you strongly suspect that your father drinks alcohol, advise him in an appropriate manner. For example, you could present him with a book or a lecture about the prohibition of alcohol and its harms, or speak to him gently and respectfully, reminding him of the Prophet’s (peace be upon him) saying: "I certainly know peoples from my Ummah who will come on the Day of Resurrection with good deeds like the white mountains of Tihamah, but Allah, the Mighty and Majestic, will make them like scattered dust… They are people who, when they are alone with Allah’s prohibitions, they violate them."

Explain to him the gravity and dangers of alcohol, and remind him of the verses and hadiths that prohibit it and warn its drinker, such as the Prophet’s (peace be upon him) saying: "Every intoxicant is unlawful, and Allah has promised whoever drinks intoxicants that He will make him drink from theenat al-khabal," which is "the sweat of the people of Hell, or the عصارة (juice/pus) of the people of Hell."

And pray for his guidance often.