One of the strongest legal bases for residency in Brazilian law — constitutionally protected by family unity.
Brazil's higher courts (including the Supreme Federal Court) have repeatedly confirmed: a foreign father or mother of a Brazilian child has the right to residency even if they entered irregularly, based on the principle of protecting family unity (Article 30 of the Migration Law + the Child and Adolescent Statute).
It doesn't matter whether you're married to the Brazilian parent or separated, and it doesn't matter whether the child lives with you daily or remotely — what matters is proving a real relationship and involvement in the child's life (material or emotional), even from a distance.
Accepted evidence to prove the real relationship:
Usually a temporary residency is granted for 2 years initially, converting to permanent residency afterward, as long as the relationship with the child continues.