Teach Neville to defend himself.

"I'll teach you some defensive spells", you tell Neville, and the other Gryffindor beams at you.

Madame Pomfrey fusses around Neville for another ten minutes. When she's done, you drag Neville out of the Hospital Wing.

"Where are we going?" he asks.

"To an empty classroom", you reply. "I'm going to start teaching you now."

You go to the Charms classroom, open the door, and peer inside. The classroom is deserted, and to your relief the cushions that you used to study Summoning and Banishing Charms. You push Neville into the room, and shut the door behind you.

"Okay", you say, turning to Neville. "Take out your wand."