Grief prolongs everything.
Every inch of Peter is exhausted beyond words. He closes his eyes and opens them again, but there's no waking from this never-ending nightmare, from the sight of Tony's charred body inches away. Shaking, numb, and so damn tired, he kneels beside the corpse of his mentor, hoping to say some rousing words that would heal everything. They had won. They had won. It would be okay, wouldn't it? But he's pulled away once again, and he's left with the unfaceable reality.
Peter is no foreigner to mourning. His mother and father, his uncle Ben had all left him in this unforgiving world, and another one has been added to the list. And then it hits him, resonates with him; this terrible outcome is here to stay. He stares at Tony's unseeing eyes and then retches, falls to the ground with no strength left, because his form of strength has been taken away, callously, carelessly, catastrophically.
"It's okay, it's okay," soothes someone through their own tears, helping Peter up and taking him into their arms. With a jolt, he realizes it's his own Aunt May. Peter's at home, in bed, not a goddamned burning alien planet that continues to imprison him. He shakes in his aunt's arms, so grateful that she's here, still around to love and embrace.
And then the memories come back in resounding lucidity, as only grief can cause. He remembers their first meeting, all the attempts to impress Tony, the hug they had shared right before it all. And Peter cries, all bravado gone, because he's just a teenage boy that might've survived death but not its impact. He'll carry the wounds just as his mentor did, contributing to his slowly rebuilding spirit, and when Peter finally joins Tony, he hopes to be able to say the words he's never said to him aloud, but words that are so true nonetheless, and also applicable to the woman comforting him.
I love you.
His aunt replies immediately, and he lets himself burrow tighter into her with everything he has. Because right now, she is everything he has.