Is the marriage considered valid if it was conducted under the guardianship of the brother, with the approval of the mother, the maternal uncle, and witnesses, and the dowry was paid, and then the father approved later, knowing that the father used to drink alcohol?

Based on the preponderant opinion in the Maliki madhhab and one of the two narrations in the Hanbali madhhab, justice is not a condition for the validity of guardianship in marriage. As for the Shafi'is and the other narration from the Hanbalis, they stipulate justice in the guardian. Accordingly, the questioner's marriage without informing her wicked father — as long as he has not left the fold of Islam — is permissible, due to the existence of an opinion among scholars validating it.