Yes prayers can change a person's life. For example there is a Saint who had a son named Augustine he was one of the biggest sinners and did a lot of bad stuff. But his mother never stopped praying for him. Then one day Augustine realized what he was doing wrong and asked God for forgiveness. And since then he grow closer to God and both mother and son are in heaven. True story.
Can God change a person's fate (or "set them on the right path") because of the prayers of other people, like parents or spouses? I would like to know if there is anything in the Bible to support this?
Some people say that God has a plan set for everyone. If that is the case then none of us have free will.