There's something at play here, between the two brothers - a dynamic that Apollo isn't a part of and isn't about to wade in to. The bruises don't alarm him - each of them can clearly give as good as they get and sometimes caring for someone is punching them in the face - so he tactfully keeps his thoughts to himself as the two exchange terse words.

"We're going to get Kylo back," He levelly explains to Declan, ignoring the fact that when said out loud it sounds completely ludicrous. Back in his homeworld popping into alternate realities was as easy as opening a door - literally - but Apollo isn't blind to how impossible the task before them is here. He just isn't going to let that stop him. Either of them.