Is someone who dies due to medical malpractice that caused him to bleed to death considered a martyr, knowing that he was 30 years old and no lawsuit was filed?

We cannot rule that your brother is a martyr simply because he died of a hemorrhage, as there is no evidence for this. The types of martyrdom mentioned in the legal texts have been previously explained. We advise you to pray for mercy upon him, seek forgiveness for him, and give charity on his behalf.