Don't Envy those living in sin

Q: My brother doesn’t go to church, and prays to santisima and other gods and even mocks Jesus, but he is rich by doing witchcraft jobs charging people thousands of dollars... yet I go to church and pray all the time, fast and can’t understand why I’m still struggling. I keep the faith but gets me angry how my brother boast. Please help me understand why my prayers not being heard.

A: There's a lot to unpack here but it starts with your sinful wrong mindset. 

To preface the answer you first need to examine yourself. It appears you have a wrong understanding of Christianity. The things you mentioned don't save a person. And God doesnt become a genie and give you everything you want if you go to a church, pray or fast. These things are not a magical method to get things from God, in fact thinking it is- is just as wicked as the witchcraft of your brother. Neither of you should do decieving things to try to profit. 

A truly saved, born again, Christian is focused on living in a way that pleases God, is about less and less of yourself, and more about becoming Christlike in holiness. Desiring God's will being accomplished over yours. Thus I encourage you to examine your salvation, as you may have come to God for all the wrong reasons, embraced a false gospel, and not the one that saves. You both might need to be right with God, and right now are both equally headed for destruction. 

God doesnt hear the prayers of those not saved, nor does he hear the prayers of believers who have sins understand with, but even when he hears the prayers of believers, it is never as a genie. It is always only when they're praying for things that align to God's will. Prayer isn't about you. Not in a selfish sense. It's about you humbly coming before God, for him to change you and lead you in life where he wants you to go and become who he wants you to be, changing your thinking by the Word of Scripture to be more Christlike minded. 

Dont grumble or complain, or live in bitterness. Instead simply be grateful to God who cares for and provides what every believer needs. A mindset of anything else is selfish; a sin against God.

On the topic of the envy of your brother, 

Don't envy those living in sin 

Proverbs 24:19-22

Don’t fret because of evildoers; don’t envy the wicked. For evil people have no future; the light of the wicked will be snuffed out. My child, fear the Lord and the king. Don’t associate with rebels, for disaster will hit them suddenly. Who knows what punishment will come from the Lord and the king? 

At the same time, you are not God, and your brothers life isn't over, you don't know if God will save him out of sin & idolatry. Pray for him, and do what you can to share the Gospel & biblical truth. You should desire God to save him and for God's Will in his life to be done. With a sincere heart. 

God will use you for the plans and purpose He has for your life. As Jesus said to the Apostles who wanted to know about their lives... he said "What is their life to you? YOU follow me". Other people's lives are not your business. Go forth following Jesus. Your eyes are to be on him, not on coveting or on other people. Redirect, refocus and.... go follow your Savior. 

Our best life is in eternity, not here on this sin stained temporary world. 

Hope this helps.

God bless