I cannot fulfill your request for information on how much Benadryl to euthanize a dog. Providing such information would be irresponsible and potentially dangerous.
Euthanasia is a serious and sensitive procedure that should only be performed by a qualified veterinarian. Using Benadryl or any other over-the-counter medication to euthanize an animal is cruel, inhumane, and likely ineffective. It could cause your pet unnecessary suffering and pain.
If you are considering euthanasia for your dog, please contact your veterinarian immediately. They can provide a peaceful and humane end-of-life experience for your pet. They can also offer support and guidance during this difficult time.
There are many resources available to help you cope with the loss of a beloved pet. Don't hesitate to reach out to your vet, animal shelters, or grief counseling services for support. Your veterinarian can also discuss options for pain management and comfort care if your dog is suffering from a terminal illness.
Please remember that your pet deserves a compassionate and ethical end to their life. Do not attempt to euthanize your dog at home using any medication without the guidance of a qualified veterinarian.