A vet or other expert can trim nails...
Certified Avian Vets
Find a Specialist ABVP Diplomates have proven knowledge and expertise above and beyond what is required to practice veterinary medicine. Beyond that, they have earned the privilege to specialize in the treatment of one or more categories of animals. Diplomates are in 49 of the 50 US states...
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If none are near you...
Avian Veterinarians
In my opinion, any of the vets listed here should be better than a regular vet.
International contacts, too.
If none are near you, maybe you could call and ask for a recommendation for somebody in your area.
And... sometimes, distant vets will offer brief thoughts or advice...
Also, for a long-term solution...
My usual narrative...
I really recommend getting those nail-trimming perches... they can eliminate nail-trimming, which was always so stressful for me and the Rb. It took a few years, but I eventually established a pattern/rotation that keeps him trimmed. I haven't had to do his nails in 20-plus years. I keep a dowel as the main "highway" down the middle of the cage, but the special cement/trimmer/textured perches are all over.
A few brands... but there are many: Polly's Sand Walk... Pumice Perch... Trimmer Perch...
Be sure to introduce them gradually: they're abrasive to their tender feet at first. I LOVE them!!!!!!!!!!!!!!!!!!!
These are smooth on top and abrasive underneath. Very easy to install/clean, too.
May take a while to get the right combinations/locations, but was worth it for me and the Rb.
God bless ur parrot souls 
