It is said going blind is the same emotions as dying and they have to go through the mourning, but once accepted they can be very happy and live very fulfilling lives. I am speaking as someone who grew up watching this happen to a VERY close relative.

She went through morning period and is a very happy person now and many people meet her and don't realize she is even blind as she does a lot and doesn't let it get in her way.

It's good you want to be supportive, but better to help her get help to move forward in life than to look for magical cures, trust me there are none with this disease. The cones and rods deteriorate and become destroyed you can't magically fix it with cannabis or vitamins.