We understand your concern and burden for your younger brother and family, Dexter2020. It is commendable that you are standing for your faith in Jesus Christ and desire for your family to know Him as well. We will pray and provide guidance based on the Word of God.
Firstly, it is important to remember that it is only by the name of Jesus that we can be saved. As it says, there is no other name under heaven given among men by which we must be saved. (Acts 4:12 WEB). The fact that we can go directly to God through Jesus Christ is one of the things that sets Christianity apart from all religions and is a source of disagreement with all religions. Jesus' last words on the cross, It is finished (John 19:30 WEB), indicates how Jesus completed the work of salvation by His crucifixion and resurrection. We must believe in Him and His finished work. Also, Jesus spoke of this previously when He said, I am the way, the truth and the life. No one comes to the Father except through me (John 14:6 WEB). Many people, with good intentions, may not know or understand this. They do not know that God loves them and sent His Son, Jesus Christ, to die for their sins. We should pray for them to have a personal revelation of Jesus Christ as Lord and Savior and maintain love, patience, and persistence in our interactions with them.
Regarding amulets and idols worship, God's word is clear, You shall have no other gods before me. You shall not make for yourselves an idol (Exodus 20:3 WEB). So we are to avoid idolatry and put God first. It is a serious matter that can have consequences. Remember how Jesus said, But seek first God's Kingdom, and his righteousness; and all these things will be added to you (Matt.6:33 WEB). Anything that replaces Gods's place in our hearts and lives is an idol. Thus, worshipping amulets, bowing to them, and denying the flesh as a sacrifice to them is a form of idolatry. We must heed the words of the apostle John as he said "Little children, keep yourselves from idols" (1 John 5:21 WEB). These practices will not lead them to the true God, Jesus Christ, but rather hinder them, as you rightly mentioned.
Here is a prayer for your younger brother and family:
Heavenly Father, we come before You in the name of Jesus Christ, lifting up Jun Wang, Poh Yew, Siow Cheng, and Yew Theng. We pray that You will reveal and save them. God, we ask You to open their hearts and minds to the truth of the Gospel. Lord put a hedge of protection around them and deliver them from the evil one. Father, we ask You to give Dexter2020 wisdom and patience as he witnesses to his family and continues to pray for them and live as a light for Christ. Let your will be done in the situation. We thank you that no one can snatch them out of your hands or the Son's hand. In Jesus name, we pray believing.
This is important. Unbelieving family members may be saved as you remain steadfast in your faith and live a godly life before them. Consider the example of Abraham and Lot. Abraham's faith was credited to him as righteousness. Because of his faith, his unbelieving nephew Lot was saved when God rained down burning sulfur on Sodom and Gomorrah and destroyed the cities and all their inhabitants (Genesis 19:24-25 WEB). God was mindful of Abraham and removed Lot from the catastrophe that overthrew the cities where Lot lived (Genesis 19:29 WEB).
We will pray for your younger brother and family to be drawn out the darkness and into God's marvelous light as they come to be save and come to a knowledge of the truth. (1 Pet. 2:9 WEB) (1 Tim. 2:4 WEB) Keep the faith and seek the Lord for yourself as you will be because of faith like Abraham a blessing to your family and God will save them because of your witness, love and faith just as the world is a better place because of Abraham's witness, love and faith.