I am in the ignore it group, you know she is capable of using cutlery so sounds like a phase or for attention. It will pass.
Probably best, I wouldn't make an issue out of it, but was thinking that if you laid the table with some nice new cutlery but said nothing, she might be tempted to use it.
Certainly, if your DS thinks it's just a phase, don't say anything.
I would buy her some children's cutlery and put it out at meal times but don't force her to use it ,perhaps she finds adult cutlery to cumbersome or is there a new baby in the house? Perhaps you could ask her why she doesn't like using a fork anymore? If she seems unable to answer you I am afraid it might just be one of those things she just has to relearn.
In some parts of the world everyone eats with their fingers. I should just let it be for now. She will learn to fit in with everyone around her or she won't, neither of which matters. What's important is that she doesn't develop eating disorders because of other people fussing about things that essentially don't matter at this stage in her life.
Possibly you should leave it. But if you do want to do anything, perhaps you can get her to start cutting up the food into bite-sized pieces before she picks it up with her fingers.
One of my grandchildren, who I love dearly, has reverted to eating with her fingers. This seems to have happened during lockdown. We looked after her as a baby and young child and she was able to use a spoon and fork and had started to use a knife. I am not just talking about finger food I mean dinners as well. She will use a spoon for baked beans or other liquid food! But not for roast potatoes, meat, veg etc. It is becoming a bone of contention between us, she is 8 years old. My son seems to think it is okay....AIBU? Should I just leave it be?