How would you deal with this and what are the potential outcomes if it is not corrected sooner rather than later? (show details)

I shall try first to explain to my team member the correct way and how it will maximize the benifits for us; but if he insist to do it the same way, then I have to go the team leader and explain the whole topic and let him act by his authority

Well thanks for inviting such a valuable discussion, hope that it will be very beneficial for all of us.

Well "Teamwork" is a very broad term. Teamwork at work helps to make new relations and to understand the work place norms. Furthermore, it helps to learn somthing about workplace spirtuality. 

Companies work hard to achieve their goals and objectives with the help of effective and efficient work of their competent employees. 

oppositly, if people are not aware of with one another, or has some sort og cultural, eithical or another sort of issues, they will never be able to towk with eachother. Sometime, they will feel hesitation, sometime they will face different sort of conflicts with working others. 

Moreover, Team work helps to enjoy the following benefits:

• Effectiveness and efficiency in work
• delegation of authority to other members who know the theme of assigned task.
• Brain storming 
• Mutual support of other members.
• Respect etc.
• Long term 
• Helps to create synergy among activities
• Helps to create a learning organiations
• Help to promote sense of achievement and motivation

If we dont move towards building a team, the members will be unable to work closely, unable to understand norms and ethics.

Furthermore, in  most worst conditions, they switching costs of the organizations will be increased, because, people needs to find fit.