The fact that she has diabetes might complicate things, but I'd try anything you know she likes, providing you can avoid anything really bad for her. Does she like sweet things? There are quite a few "diet" versions of sweets and puddings that might be suitable - I'd guess you need to check with the dietician or doctor first.
What about taking your blender to visit and making her a fruit smoothie (eg. banana and milk whizzed together)? She might only take a little bit but at this stage it seems anything is probably better than nothing.
This is such a hard thing to manage for you. Have you tried to get the SALT (Speech and Language Therapist) to see her yet?? Some people on TP have found this helpful in similar circumstances.
