How to improve my lucio's low defensive assist stat?

That’s because I didn’t have specific advice for that. It was a rather vague question, honestly.

I don’t know if he should amp up when his allies are at half health. Does he have another healer topping them up?

Is he solo healing?

Or is his other healer like a Zen or something?

Edit addition because this was a big one I forgot: How fast are they taking damage?

I don’t know, so I can’t say. These things change the answer to some degree.

That’s why in my advice I said to look at the specific instances instead of at the whole or at the stats.