As far as I have understood, God can forgive all sins (Romans 5:8, 1 John 1:9), least blasphemy against the Holy Spirit (Mark 3:28-29), and that we are not to judge (Matthew 7:1, Luke 6:37, John 7:24) , God is the only one (James 4:12) and that we shall forgive (Matthew 6:14-15, Matthew 18:21-22), however, we shall exhort us (Galatians 6:1, 1 Thessalonians 5:11, Hebrew 10:25), not to point to each others as sinners (we all are; Romans 9-26), but in love (Romans 12:8). As a sinner we shall live in repentance, say "I made a mistake and will (try to) not make this mistake again" (Matthew 3:8).
However, sins are often times discussed as a terminal action (e. g. a lie) and even if repetitive as an ongoing sin (e. g. notorious lying). But what about a continuous sin, a sin one cannot come out as easy as one might wish to (an illicit marriage)?
I will rephrase my question (from here: soteriology - How can a person in this situation be forgiven his sins? - Christianity Stack Exchange) in more general terms. My question is twofold.
a) How to position oneself, a practicing Christian, towards a person as described below in your live (family member)? b) What can a person in the described position do to be saved, do go the right path, Gods path?
I believe to not have found an answer to both questions directly.
Imagine a self-identified Christian (evangelical) who married his first woman in civil union and in church, has two children who he not educated the faith, and who he abandoned after being unfaithful to his first wife several times. He was divorced by his first woman on civil terms, however, he was not reputed for his sins to a church member (or at all). Hence, divorced by law, not by the terms of the bible (Matthew 5:31-32).
He then married in civil union only a second wife, which he divorced without children.
Lastly, he married for a third time in civil union and in church (for a second time), with which he had fathered a baby now.
To my understanding of the scripture, he was never repented by his first wife of unfaithfulness (Matthew 19:9), meaning that he would still married by church to his first wife (Mark 10:8-9), meaning all his following marriages are illicit.
Now, the problem: how does he (if he wanted to) come out of this situation or his he doomed to continue sinning?
Let me rephrase: to most Christians, an homosexual marriage or union would not be considered licit by the bible (Leviticus 18:22 and 20:13) and he homosexual person living in an union like this who would say that he did wrong marrying a same-sex person was wrong, continuing living so, would not be believed. Why then a man who continues to live in an illicit marriage to a woman?
I pray and prayed for this person especially for Hebrew 3:13 and Hebrew 6:4-6, but do not how to position myself. Play along? Exhorting?