Sin Unto Death Explained

I was asked about these verses by a dear saint (1 John 5) and in this short article, I will cover what seems to be the best explanation for it. 
Here is the verse that has stumped and caused many to wonder its real meaning:
 If any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. There is a sin unto death: I do not say that he shall pray for it. All unrighteousness is sin: and there is a sin not unto death.
This is a very difficult verse and right off I want to say; unlike most of God's Word, this verse is hard to be TOTALLY dogmatic on and say 100 percent we know what it means exactly and fully. Having said that, I will offer the best reasoning on this verse that I know of after my study on it to help. (men if you know a better way email me on it)
First. I have researched and there are about 4 main possible views on what this verse could mean. I myself studied them out and I find them all very lacking so I am not going to mention them here. I do not want to propagate their belief and confuse others.  
As always, we use scripture to help us understand scripture. 
  This verse says : 
If any man see his brother sin a sin which is not unto death
We know from all of scripture, all the way back to the garden, that ALL sin does lead to death. Both physical and spiritual. That has not changed in Johns mind/theology as he knows this. So we can only assume if we see a brother sin and he does not die, this is what John is referring to here as all sin will lead to hell and death without Christ and repentance. It is physical death John mentions over a certain sin that he does it would seem. But what sin? Some have said the unpardonable sin (blasphemy) but I think not as I will show that other sins kill people as well. 
Let me give you examples in the Old Testament where God killed people physically over one sin like Exodus 32:27 and 2 Sam 6:7 / Then closer to Johns time; we see examples in the New Testament of this same thing in Acts 5:5, Acts 12:23 and 1 Cor 11:30 
God had all along done it and was still killing people on the spot over certain sins. This is THE only good and solid explanation to Johns writing that I have been able to come to. What sin and why, we just cannot say.  
The next words in our text say: 
he shall ask, and he shall give him life for them that sin not unto death.
John is saying to the brother watching a brother in sin, pray and ask for life for the man in sin. Meaning he has life/breathe still, God has not killed him over the sin and so there is hope. We would pray for repentance as we know the ONLY remedy to sin is confess and be cleansed new by Christ. See 1 John 1:9 
The next verse says:
There is a sin unto death: I do not say that he shall pray for it. 
This is the very hard verse to fully grasp. In the context, the best explanation is that as in the examples I gave you; there are sins (no matter which one it is) that DO at times lead to death penalty on the spot. John is saying if that was to be the case do not pray for (against) that. God is acting by His shown will to judge that persons sin and who would want to pray against that act by the Creator? 
    The next verse says:
All unrighteousness is sin:
As I stated, this is a given and we know all sin is a reproach to a Holy God so we should flee them all.
Then he says:
 and there is a sin not unto death.
John seems to be saying the obvious, that not all sin means instant physical death. We do know all sin is a path to death and hell. John says this is verses in the same chapter:
We know that whosoever is born of God sinneth not; but he that is begotten of God keepeth himself, and that wicked one toucheth him not. And we know that we are of God, and the whole world lieth in wickedness.
Let us not ever read into the Word what is not there.
It is a dangerous practice to ever build theology on what we cannot be dogmatic about like this verse. If we study and read the entire scriptures, it help us to balance out our views and not go into a theological ditch. There is NOTHING in the rest of God's Word that leads us to believe some of the crazy ideas I have heard men say about this verse. Do not go there saints!
We know dogmatically..... 
* All sin will damn you and its why your body dies and men face hell
* We are called to repent and leave all sin, big or small.
* We are not to stay in willful sin as it is not covered by Christ Heb 10:26
* God alone knows why / how he kills some people asap or allows wicked men to live on for decades.  
* Perhaps this is the reason we should all live in FEAR and trembling as Paul says in Phil 2
* Jesus warned us to FEAR God who can destroy body and soul and it is more evidence to back up this verse explanation
In closing, I have come to realize sometimes in our studies; we cannot know it all here on earth. Faith is trusting what we cant see and sometimes that is all truth/clarity on certain topics. I believe this is one such topic so handle it with great care.
We should NEVER question God due to our lack of understanding on deep topics. But; we should fully trust Him. 
 God said to Job:
Where wast thou when I laid the foundations of the earth? declare, if thou hast understanding. Who hath laid the measures thereof, if thou knowest? or who hath stretched the line upon it? Whereupon are the foundations thereof fastened? or who laid the corner stone thereof; Job 38:4
The best advise on these verses is to NOT live in or keep on going sin and we will be safe from God judging us to death on the spot; for the most part. John did not take sin lightly and neither should we.  
Here is a article on strange fire and how God judges people to death:
http://spiritandtruthdiscernment.blogspot.com/2021/12/christmass-is-strange-fire.html
See this article about Gods judgement on men:
http://spiritandtruthdiscernment.blogspot.com/2020/09/1-corinthians-55-explained-destruction.html 
God be praised