Yes, true Christian parents must disown their child who is a homosexual. This is what is taught by the excommunication principle of the New Testament. Excommunicating a person from the church necessitates disowning that person from your family. The homosexual influence must be driven out of your family in order to protect your wife, your other children, and your relatives and friends from being led astray into homosexuality by your gay child.
Every Christian politician must publicly disown their gay children. This is demanded by Jesus Christ, who is God, who destroyed Sodom and Gomorrah, rather than send missionaries to save gays. Sharing the Gospel with gays is forbidden in the Holy Bible. This is clear in both the New Testament and the Old Testament.
Christians must speak against homosexuality, aggressively, in the family and at church and in town settings to prevent the evils of homosexuality from proliferating in your town. It is important to speak out against homosexuality publicly.
Jeremiah 5 shows that God did NOT forgive Jerusalem, because evil proliferated. It is necessary to disown your homosexual children and not speak to them or see them. This is the requirement of your God. The God of the Holy Bible.
All you need is Jesus Christ. Jesus Christ is sufficient for you, even if you disown your only child who comes out as gay. You must love the LORD your God with all your heart, mind, and soul. This is the greatest commandment of the New Testament.