Mitsuya cared. Like, a lot.
He wanted you to know that too, that it wasn't your fault Draken died in the Battle of Three Deities nor that Mikey left Toman and went off to make the Kanto Manji Gang in the first place. Because how could he be mad at you? You were precious, weak as ever but he thinks that's why he likes you. Additionally, you reminded him of his sisters Luna and Mana which automatically made him gravitate towards you more than he realized.
Everyone else was there for you too. So hopefully you would be up and at em', ready to get out there again sooner or later. But for now? He just wants you to rest a little bit longer... God knows you need it, and ,of course, he'll be there for you every step of the way like a loyal member would.
You are their Commander now, sure most of Toman's members left with Mikey but there were plenty of new members that came with you. Mitsuya thinks it's amazing how you're just able to soften the coldest of hearts and convince some of the meanest gangsters out there to put aside their differences and work together, he would say it's the best talent to have in times like this where betrayal is like second nature to most.