user47483: My friend doesn't listen to his head of engineering and doesn't fully understand how decentralized consensus based systems like Bitcoin really work. He seems to think a new untested/buggy implementation with conflicting consensus rules can be made to work with the existing implementations that follow existing consensus rules. 
What advice can I give to him?

user5406: You may be approaching this from the wrong angle, if you want to directly jump to giving your friend advice.
It is my experience that conversations addressing strong convictions that aren't based on evidence can easily make people feel patronized or even antagonized. You'd have to find time with your friend to really share opinions in a non-confrontational way. This works best in a private setting and with a small group.
Try to create an open-minded atmosphere. You must be willing to listen to your friend, in order to find out what his understanding of the situation is and what he hopes to achieve. You may need to allow them to discover for themselves that they don't have a full understanding of the situation. Only when they actually question their conviction, there is a chance to introduce some new thoughts without them being dismissed. This is when you offer them a few points or question to think about, but don't ambush them with a compendium of information.
Alternatively, if your friend has very little time, you could get someone to compile a succinct yet encompassing report with presenting a balanced overview of all important aspects of the situation.
Alas, it may be that your friend will not be convinced by your effort. He may already assessed the available evidence and come to a different conclusion, or perhaps have different priorities in this situation than you. At that point you might find it expedient to agree to disagree, and let them make their own decisions. Perhaps they turn out to be right, or they'll have a chance to learn from their mistake.

user47486: He should listen to his engineer. I think that's just about it. 

47483: <p>My friend doesn't listen to his head of engineering and doesn't fully understand how decentralized consensus based systems like Bitcoin really work. He seems to think a new untested/buggy implementation with conflicting consensus rules can be made to work with the existing implementations that follow existing consensus rules. </p>

<p>What advice can I give to him?</p>
 5406: <p>You may be approaching this from the wrong angle, if you want to directly jump to giving your friend advice.</p>

<p>It is my experience that conversations addressing strong convictions that aren't based on evidence can easily make people feel patronized or even antagonized. You'd have to find time with your friend to really share opinions in a non-confrontational way. This works best in a private setting and with a small group.</p>

<p>Try to create an open-minded atmosphere. You must be willing to listen to your friend, in order to find out what his understanding of the situation is and what he hopes to achieve. You may need to allow them to discover for themselves that they don't have a full understanding of the situation. Only when they actually question their conviction, there is a chance to introduce some new thoughts without them being dismissed. This is when you offer them a few points or question to think about, but don't ambush them with a compendium of information.</p>

<p>Alternatively, if your friend has very little time, you could get someone to compile a succinct yet encompassing report with presenting a balanced overview of all important aspects of the situation.</p>

<p>Alas, it may be that your friend will not be convinced by your effort. He may already assessed the available evidence and come to a different conclusion, or perhaps have different priorities in this situation than you. At that point you might find it expedient to agree to disagree, and let them make their own decisions. Perhaps they turn out to be right, or they'll have a chance to learn from their mistake.</p>
 47486: <p>He should listen to his engineer. I think that's just about it. </p>
