We are truly sorry to hear about the struggles you and your family are facing, and we are here to pray for you and guide you according to scripture.
Firstly, in the Bible, Jesus emphasizes the importance of praying in His name. As Jesus said, "Whatever you will ask in my name, that will I do, that the Father may be glorified in the Son. If you will ask anything in my name, I will do it." (John 14:13-14 WEB). This is also especially important as it is only by the name of Jesus that we can be saved.(Acts 4:12). We are glad you acknowledge Jesus' help in your request, because we must each come to Jesus in belief and accept that He is the Son of God. “Jesus said to him, "I am the way, the truth, and the life. No one comes to the Father except through me."” (John 14:6).
From your request, you should not let worries overwhelm you. As Christians, we're called to be compassionate and support, but also to put all our cares onto Jesus. "Humble yourselves, casting all your worries on him, because he cares for you." (1 Peter 5:7 WEB).
When you said about your brother's actions to your mother - that is not the Biblical ideal that is outlined in Ephesians 6:2, which tells us to "'Honor your father and mother,' which is the first commandment with a promise". It's even more concerning that this may be stemming from mental health issues and violence that everyone is ignoring. There may be things taking place that are causing all parties to lack wisdom and understanding of what is right (Proverbs 24:3, Proverbs 4:7,). It is important that these issues be not ignored, but faced, and then shared with the family to have the greatest beneficial outcome.
From your words: "She has to check with him if she needs to take a walk ( usually it's not often ) and he makes her live a nightmare." This does sound like manipulative control and abuse that has to stop.(Galatians 5:16).
About you feeling you can't do anything to help as she doesn't want any help: Firstly, obey the scripture of Isaiah 30:1. If you follow all of the scriptures about this it guarantees you will be saved, but as Luke 13:24,3,5 says there is a judgement between those who are called, and those chosen.
Here's a heartfelt prayer for you and your family:
Dear Heavenly Father,
We come before You in Jesus Christ's Name, lifting up this family that is facing immense struggles. Lord, You know the depth of their pain and the complexity of their situation.
Father, we pray for the mother, that You would grant her a situation that is peaceful, free from fear or control, and safe (Psalms 4:8, Psalm 34:17,), that You would guide her steps (Galatians 5:25), and give her wisdom. We also bring the brother before You, asking that You would heal his mind (Matthew 4:24,), and draw him to Yourself (John 3:16), showing him the importance of honoring his parents and living a holy life.
We pray that when this family is experiencing lack of trust as mentioned in 1 Corinthians 13:7 and Proverbs 3:5 that all parties seek information to help them come to a correct shared understanding.
We pray this in the name of Jesus Christ our Lord, The Holy Spirit, and our Heavenly Father.
In the name of our Lord Jesus Christ we pray,
Amen.
You and your family, and especially your brother are in need of God's word, The Bible, counselling, and/or treatment from suitable medical professionals. Seek out any valid information that may be beneficial to assist decision making.
Hi everyone! 
Let's lift up 
@Zian needs prayers for land issues, job, and health concerns.
