Can this de-ionized water be used for DRINKING? Water that is advertised mainly for car batteries doesn't sound so.
I know someone who had a heart transplant and could only drink distilled water as all bacteria & organisms in the water is killed off & removed during the heating & distillation process.
The OP needs it for a CPAP machine in which a mask is placed over her DH's nose & mouth all night so he can breathe. It has to be routinely sterilized so one doesn't get an infection. I assume the distilled water is for that.
Here is a link saying the two waters are different and de-ionized water may not have the bacteria & organisms removed.
https://www.uswatersystems.com/deionized-water-vs-distilled-water