My dear brother in Christ, you are absolutely right. God can speak the word and it will be done. But, we must remember that faith without works is dead. I have prayed for many that want marriage restoration, but they don't want to do the work to make the marriages better. Now, don't get me wrong, I am not saying that it was your fault or hers. What I am saying is that it is a lot of work to get a marriage in order, aligned with God's plan.
Yes, I will hold this marriage up in prayer. But, before God restores this marriage, please take a look at what tore this marriage apart and work on it and pray about it daily. It is so hard sometimes for us to change our way of thinking. If you were leaving the cap off the toothpaste, just be mindful to put it on next time. Amen. If she forgot to leave the seat up for you, then she must be mindful of your needs. Please, just know that there is always a reason for broken marriages. If it was infidelity, that will take quite some time to heal. I pray that this wasn't the case. But, God can do all things. He can even heal that. But, we must make it up in our minds that we won't follow that pattern again. Please brother, listen to me. God can restore anything that the canker worm has stolen from you. But, you must be strong enough in Christ to defeat this canker worm when it comes your way again. Put on the whole armor of God.

Father God, in the mighty name of Jesus, please heal my brothers marriage. He needs to feel your presence in his marriage and his life. Let him know that you love him Lord. Guide him and lead him to do what is good and righteous in Your sight. Touch my sister that she will have a forgiving heart. Speak to her soul that she may want to fix this marriage.
I pray to Your mercy for this marriage Father.
I ask this in Jesus Holy name, Amen!