I don't know very much about diabetes, and it's been years since health class and biology class, so please do be aware that this is totally a layperson's opinion. First, malt is a sugar, it comes from maltose, which is supposed to be healthy because it's produced when the seeds of a grain have begun to sprout. I don't know if diabetics can't process
glucose which is unhealthy to anybody in excessive amounts but of course especially dangerous for diabetics, as opposed to something like
fructose which is usually only toxic when you don't also eat it with fiber--according to
this lecture I saw on the University of California YouTube channel, but that was less about diabetes and more about hypertension and cardiac problems that have nothing to do with dietary fat.
If, as I've heard, fiber helps people to process sugars more effectively, then perhaps adding a cup of bran that has soaked in buttermilk for ten minutes, would make it healthier. It would change the texture, of course, but it would be healthier.
As for the actual sugar, I've heard that coconut palm sugar, which is made from the nectar of coconut tree flowers, has a low glycemic index that makes it better for diabetics than regular sugar. I don't know if it would be better for diabetics than
Splenda, but there's that option too. Of course, that's probably an adventure in flavor, and a bit of a risk if it turns out that your neighbor is allergic to coconut or something...
Still, I hope this helps!