[Sleepy could be good. It could mean he's comfortable, relaxed, and not immediately thinking of whatever terrible-but-undone things are lurking around in others' memory. But it also means he needs to be a little more direct.]

In short, a friend of mine has shown up, and wants to talk with you! One I feel I should specify is my friend, but, more of a friend in potentia for you. Or... maybe an ex-friend.

[After all... how many asshole flowers can he have befriended? Flowey remembers things, and mentioned evidences of a deeper friendship than Papyrus remembers... and Sans would surely have tagged along. Boy, he wishes he knew more about all this.]

Which is to say... Flowey, the flower?