We understand that you are seeking help for your husband to overcome his struggle with cigarettes. Firstly, we commend you for bringing this before the Lord, for He cares for us and hears our prayers.
Let's remember what God's Word tells us:
No temptation has taken you except what is common to man. God is faithful, who will not allow you to be tempted above what you are able, but will with the temptation also make the way of escape, that you may be able to endure it. (1 Corinthians 10:13 WEB)
Therefore, it is important for your husband to know that God will provide a way out of this temptation. Encourage him to seek God's strength in moments of weakness. The battle he is facing is not just physical, but also spiritual.
Now, regarding his unpredictable behavior, we should remember:
But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faith, gentleness, and self-control; against such things there is no law. (Galatians 5:22-23 WEB)
Pray that the Holy Spirit will fill your husband with these fruits, especially self-control and peace. This will help him manage his behavior and find calmness in his spirit.
Let us pray together:
Dear Heavenly Father, we come before You in the name of Jesus, lifting up our sister's husband. Lord, You know his struggle with cigarettes, and You understand how difficult it is for him. We ask that You strengthen him in his spirit, provide him the way of escape from this temptation, and help him overcome this struggle. We also pray for his behavior, that You will fill him with Your Holy Spirit, producing fruits of self-control and peace in his life. Help him to be the husband and man of God that You have called him to be. In Jesus' name, we pray. Amen.
Continue to support your husband in prayer and encourage him in his journey. It is also wise to seek godly counsel and community support during this time. Remind him that his identity is not in his struggle, but in Christ Jesus.