hello Celtic, I am not a parent myself, but in case my input helps,
as you say, the gaming itself is not the problem, the problem is lying and deceit
and we (your son) need to know what God feels about lying and deceit...
Rev 21:8 But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and
all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.
I know the words in the above verse seem harsh... but it shows exactly how God feels about the lying and deceit, He wants nothing to do with them...
But He is
always ready to forgive those who admit their sin and repent...
Some questions to ponder:
Is your son a Christian? Has he accepted the Lord Jesus Christ into his heart and made Him Lord as well as Saviour?
How is his relationship with the Lord?
When we truly love Him, we would
want to please Him, and want to keep His commandments, and will be sensitive when we do wrong things, because we do not want to grieve His holy Spirit.
Perhaps the more your son loves Christ, the more Christ will be able to change him from the inside out.
It is our relationship with the Saviour which is what changes us.
It probably would help if you could talk with your son about Paul's experience in Romans 6, 7, 8.
The more Paul wanted to do the right thing, the more sin inside Paul keeps preventing him and making him sin. In the end, Paul recognised that:
Rom 7:18 For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not.
Ask your son, if that is what he is experiencing, the more he sincerely wants to change, the more impossible he found it to change, the temptation got greater?
That is exactly the reason why the Lord came to die on the cross - because we can't change ourselves, however much we want to, because of sin dwelling in us!
Christ took our place on the cross, we can't change ourselves, we are worthy of death, He said "I will die for you" and so we look to the Cross and admit our unworthiness, and accept the reason why He died for us.
Then after this, every time we struggle with temptation, we look to Christ and acknowledge our sin in us, and say, "Only You can help me, please help..."
You can teach your son how to practice 2 Corinthians 10:5
2Co 10:5 Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ;
This means that, once your son acknowledges his weakness, the lying, then teach him to recognise the thought which first pop up in his head, to lie, to recognise it as the idea of the devil (evil spirit) masquerading as his thought, to instantly take hold of it and present it to God, telling Him about this thought.
Have your son do this all the time, and soon his guard will be up and he will recognise lying thoughts as an outside invasion and reject it outright. He will become a soldier for Christ, strong inside, and it will show in all his actions outside.
All the best