Your assesment is correct - especially at your level, it's basically "Make sure Protect was on and spam Cure". There's very little you can actually do to amplify your healing capabilities beyond that. Similarly, that tank has very little mitigation-related abilities at that level and is tanking purely on raw stats pretty much. Even if pre-Halatali dungeons don't hit hard, they can still overwhelm players who get cocky.

At later levels you'll start having vastly more tools to save tanks from their own stupidity; but that's later.