Hi there, sure no problem going DIY is a great way to try and help, you’ll also need the Noahlink Wireless programming device for your DIY projects, here’s the connexx user guide which is very helpful in your case,very easy to follow, once you have installed connexx just make up a demo client, enter his audiogram and then have a play around, you’ll get the hang of it pretty quickly.
Now for tinnitus controller, i believe Signia has one of the better ones, i can’t speak for the “Notch Therapy” teaching the brain to ignore it is hard, masking seems easier and much more common way.
User Guide.