There are three divisions of the church, namely:
1. Church Militant - composed of Christians here on earth who are struggling against the devil, sin, the world and the flesh. We, the living, belong to this Church.
2. Church Suffering - means the souls in purgatory, and
3. Church Triumphant - comprised of the saints in heaven.
The Church Suffering cannot help themselves but we, the Church Militant can help them by praying for them and by offering sacrifices for them.
I read so many books about the souls in purgatory, and I found out how badly they need our help. So let's pray for them or better yet have a mass said for them.