Your prayer coming as little children in simple faith is precious to hear, and it honors the Lord. You have anchored it well in who He is. He is able to save completely those who come to God through Christ, because Jesus lives to intercede for us, and nothing is impossible with God. The things that are impossible with people are possible with Him, and He is fully able to do what He has promised.
You asked about dreams while sleeping, and Scripture does show that God has spoken in that way. The Lord said that He would speak to prophets through dreams and through visions, though He spoke with Moses more directly. In Job we read that God does speak, now in one way, now in another, though people may not perceive it, in a dream, in a vision of the night when deep sleep falls on people as they slumber, to warn and to turn them from wrong and to keep them from pride and to preserve their lives. Joel promises that afterward God would pour out His Spirit on all people, so that sons and daughters would prophesy, old men would dream dreams and young men would see visions. That promise points to the generous outpouring of the Spirit.
We see this pattern through the Bible. God spoke in dreams to those who belonged to Him and also to those who did not yet know Him. He warned Abimelech in a dream, He warned Laban, He gave dreams to Pharaoh that troubled him, He gave dreams to Nebuchadnezzar, and in the New Testament He warned Joseph in a dream to take the child and flee to Egypt and He warned the wise men in a dream not to return to Herod. In many of those cases the dreams came in pairs or needed an interpretation, and no magician or wise man could explain them. Joseph himself said it was not in him, but God would give the answer. That is an important reminder. When God does speak in this way, the understanding comes from Him, not from human wisdom.
I am open to the Lord speaking through a dream or a vision and would find it a wonderful thing if He chose to do so, but I have learned not to seek dreams as the main way of hearing from God. His most sure and steady way of speaking to us is through His Word, which is a lamp to our feet and a light to our path. Any dream or impression should be tested against Scripture and held humbly before Him. We do not command God to speak on our terms, but we come with humble confidence, asking according to His will and thanking Him in advance, trusting that His arm is not too short to save and that Jesus Christ is the same yesterday and today and forever.
Your heart for your wife in this prayer is also beautiful. From the beginning God made them male and female, and His perfect design for marriage is that a man leave his father and mother and cleave to his wife and the two become one flesh, what God has joined together. A husband caring for his wife and seeking her spiritual good reflects that one flesh calling. Whether God answers this specific request with a night dream or in another way, keep loving her joyfully all the days God gives you, covering your home in prayer and in the holy environment that faith brings, and keep seeking to please the Lord together.
So let us pray together with you. Father, we thank You that You can do all things and that You live to intercede for us through Christ. We ask that You would speak clearly to this wife and to this husband and to all of us, that You would turn hearts from wrong, keep us from pride, and preserve us from the pit. If it pleases You, give dreams or visions that underline Your will in Christ Jesus, but above all make Your will known through Your Word and by Your Spirit, and give faith to receive it. We trust You to lead, to protect, and to save, and we thank You in advance because we know You hear those who come through Jesus. In Jesus name, amen.