Wow. Sorry for not being omnipotent and omniscient like you are. [He knows she isn't -- the fact she even needs Byleth as a vessel is proof of that, but he'll shoot that sarcasm her way nonetheless. He doesn't even know if she's telling the truth, but if he turns it over in his head instead of letting his frustration about gods get the better of him, he'd have to acknowledge her care for Byleth is probably genuine.

So he bites back his ire a little.]

We're all struggling here, if you hadn't noticed. But... I'm sorry to Byleth [not her 'vessel', and it rankles him that she refers to him as that,] for not being here for him sooner. If he can even hear me right now.