We understand your concern for your brother and your family, and we commend you for your love and compassion. Let us first address the issue of salvation. It is only by the name of Jesus that we have access to God. As it is written in Acts 4:12 WEB:
And there is salvation in no one else, for there is no other name under heaven that is given among men, by which we must be saved!
It is clear that your brother is struggling with various issues, and it is important to remember that spiritual problems often manifest in natural ways. The Bible tells us that without the Holy Spirit, one may easily fall into sin. Galatians 5:22-23 WEB lists the fruit of the Spirit: love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control. The absence of these traits in your brother's life indicates a spiritual void.
First, let us pray for your brother:
Dear Heavenly Father, we come before You in the name of Jesus Christ, lifting up the brother of Sister Ambria. Lord, we know that You desire for all to come to repentance and be saved. We pray that You will have mercy on him and draw him to Yourself. Convict him of his sins and help him to see his need for the Holy Spirit. Give him the strength to turn from his wicked ways, to be filled with the Holy Spirit, which is also a sign of salvation. Help him to live a life that is pleasing to You. In Jesus' name, we pray.
Now, let us address the specific behaviors you mentioned. The Bible is clear about the sins of lying, stealing, and laziness. We read in Colossians 3:9-10 WEB:
Do not lie to one another, seeing that you have put off the old man with his doings, and have put on the new man, who is being renewed in knowledge after the image of his Creator.
Ephesians 4:28 WEB says:
Let him who stole steal no more; but rather let him labor, working with his hands the thing that is good, that he may have something to give to him who has need.
In regards to laziness, 2 Thessalonians 3:10 WEB reminds us:
For even when we were with you, we commanded you this: If any will not work, neither let him eat.
Regarding his relationship with his girlfriend, let us remind you of the biblical principles for relationships. Your brother should be seeking a godly spouse, not just a girlfriend. If they are not married they should be courting with the goal of marriage. It is written in 2 Corinthians 6:14 WEB:
Do not be unequally yoked with unbelievers, for what fellowship have righteousness and iniquity? Or what fellowship has light with darkness?
Concerning his lack of hygiene and carelessness, these are not only personal issues but also affect others. He should be reminded of Philippians 2:3-4 WEB:
Do nothing from selfish ambition or conceit, but in humility count others better than yourselves. Let each of you look not only to his own interests, but also to the interests of others.
Let us also pray for you, your sister, and your mother as you embark on a 7-day fast:
Dear Lord, we pray for Sister Ambria, her sister, and her mother as they dedicate this time to fast and seek Your face. Strengthen them, Lord, and help them to maintain their focus on You. Give them the guidance and discernment they need, and help them to be examples of Your love and grace to their brother. In Jesus' name, we pray.
Finally, remember the power of your testimony and love towards your brother. Be encouraged by 1 Peter 3:15 WEB:
But sanctify in your hearts Christ as Lord, and always be ready to give an answer to everyone who asks you a reason concerning the hope that is in you, with humility and fear.
Continue to show him love, pray for him, and be a positive influence. Trust that God is at work in his life, just as He is in yours.