Let us begin by remembering the words of Jesus in John 16:23-24 WEB: "Most certainly I tell you, whatever you may ask the Father in my name, he will give it to you. Until now, you have asked nothing in my name. Ask, and you will receive, that your joy may be made full." It is so important to pray in the name of Jesus, as it is through His name that we have access to God the Father and it is only by Christ that we can be saved and have access to Heaven. Please remember this and apply it to your life.
Firstly, let us pray for your son. We see in Ecclesiastes 9:10 WEB: "Whatever your hand finds to do, do it with your might;" We pray for your son to have endurance and to be a good testimony in his workplace.
We see in Proverbs 3:3-4 WEB: "Let not kindness and truth forsake you. Bind them around your neck. Write them on the tablet of your heart. So you will find favor and good understanding in the sight of God and man." We pray that he does his work with integrity and finds favor with God and his superiors.
In preparing emotionally to become a father, we remember Hebrews 12:7 WEB: "It is for discipline that you endure. God deals with you as with children, for what son is there whom his father does not discipline?" We pray for God to grant him wisdom, patience, and love as he prepares for this new responsibility. You mention you want prayer for his wife and their child. We assume your son and his wife are married as this is commanded in the scripture before having a child. If this is not the case, we pray for them to be convicted and make their family legitimate in the eyes of God.
Concerning the healing of your relationship with your son, we recall Colossians 3:13 WEB: "bearing with one another, and forgiving each other, if any man has a complaint against any; even as Christ forgave you, so you also do." We pray for both of you to forgive and grow closer, for you to be a wise and loving influence in his life and in the life of his new family.
For your daughter, we read Isaiah 41:10 WEB: "Do not be afraid, for I am with you. Do not be disappointed, for I am your God. I will strengthen you. I will help you. Yes, I will uphold you with the right hand of my righteousness." Be praying for her strength and the health of her and her baby.
For your mother, we remember Psalm 71:9 WEB: "Do not cast me off in the time of old age. Do not forsake me when my strength fails." We pray for her to receive compassionate care and comfort in her later years.
It is important also to be sure all your family knows Jesus Christ as their Savior. Remember and share with your family John 3:17-18 WEB: "For God didn't send his Son into the world to judge the world, but that the world should be saved through him. He who believes in him is not judged. He who does not believe has been judged already, because he has not believed in the name of the one and only Son of God."