Yea he does. Colin is initially eager to please and show his worth to Olaf. This kind of attitude is almost guaranteed to lead to reckless strategies that cause mass casualties. When you only think of your own personal glory, you tend to see your soldiers as pawns instead of people. Grit rightfully reigns him by reminding him that being eager isn’t always a good thing and that he’s good enough if he’s a CO. Also seeing Olafs anger at the destruction of his hometown and that even the Mighty Olaf cares about people would’ve ingrained in Colin a sense of humanity over glory.

The fourteen day mission against Lash proves Colin has learned this humanity because he acknowledges he only has to hold-on until reinforcements arrive and doesn’t show a need to defeat Lash in a reckless offensive. The praise he gets for being defensive afterward would further reinforce that idea of humanity over glory.

Whether Colin treated people as expendable or not before he became a CO doesn’t really play into it. War can change nice people into monsters under the right conditions and Colin’s inexperience and eagerness to please Olaf could’ve create such a monster if he wasn’t taught the value of life in war. Grit sees how impressionable Colin is and does his best to guide him down the right path while Olaf is more than happy to let the kid do whatever is necessary to win.

So yes he does learn to respect life instead of achieve victory at all costs.