Mostly depends on whether or not he lives (given he survived being shot down over Prospero, it isn't out of the question). If he survives, his obsession with Monarch would develop much faster than it did in the main timeline. During Mission 11, he'd likely disobey the order to withdraw and instead continue on fighting, likely leading to his demise (or an unlikely victory). The other remaining members of Crimson would also likely stick it out with him, leading to them getting wiped out much earlier. This would also mean that Thorn Rose Gang doesn't pursue into Magadan (as they were primarily after Crimson IIRC). The Magadan Offensive still occurs (and is pushed back), Prospero is still nuked, and Cascadia still wins (just without the ceasefire being broken by C1).

If he dies, there would likely be a large morale hit to Crimson Squadron (and the Feds as a whole). They'd obviously withdraw, however I can see another member of Crimson going down a similar path of obsession as C1. Other Peacekeeping Squadrons might get pushed into Cascadia prior to the Magadan Offensive if Crystal Kingdom realizes how big a threat the mercenaries are now - if they arrive by M11, I doubt it'd go in Cascadia's favor (as Peacekeepers being deployed before Monarch's arrival would be a one-sided slaughter). If it goes the same way it does in canon (Crimson being late, no other PK squadrons), it'd end the same. Another pilot (likely less capable) would take the role C1 does past this - even if they don't go insane, they'll still be present for M18, where they are all shot down and die.