Sirius knew some basic healing spells, but he wasn't about to test them out on her. He definitely didn't want to make things worse than he apparently already had.
So he ran and got her some water, and grabbed some pill bottles out of her cabinet, hoping that he grabbed something that would help. Not that he had any idea - even if he'd known British muggle medicines, these were all different.
He came back, throwing them on the bed beside her.