This is actually really good writing. Mc is someone who, after trying, spent 3 years alone, doing nothing. No matter what happens, that's not something you can change with just a few weeks or months of exposure. It's something he has to work on, and something he clearly is changing, seeing how he reacted to the pres' response. The story is very clearly showing that even if he does try, it still takes baby steps to get out of your comfort zone. His loner talk is just his self-defense mechanism, and something he has had to rely on for 3 years. No one can just move on.
Also, he's a teenager, give him a break.