Aloha! You're speaking to Dr. Michael Salkin
I'm sorry that your question wasn't answered in a timely manner. To answer you directly, yes, I'd like you to solicit the help of a veterinary specialist behaviorist rather than a trainer as can be found here: www.apbc.org.uk It's important that such a professional comes to your home in order to better understand the dynamics therein and return periodically for progress reports and perhaps to modify the reconditioning program. I can give you basic instructions for separation anxiety (see below) but they shouldn't substitute for up close and personal attention from a professional.
The discussion of separation anxiety is exhaustive - lectures I've attended encompass hours on this problematic behavior alone. I can, however, give you a synopsis of its management that should be helpful. If possible it would be best if you could have a board certified animal behaviorist come to your home to better evaluate the dynamics that exist there. His vet should be able to refer you to such a specialist or you can find one here: www.apbc.org.uk.
Step 1) Change the relationship - Teach Buddy independence. He should not be allowed to get attention on demand. When he gets what he wants every time he nudges or whines, he is more likely to be anxious when he is alone and can't get social attention. You can give him attention when you so desire but it must always be on your terms, not Buddy's.
Step 2) Departures and predeparture cues - Departures should be kept as calm as possible. The presence of certain departure cues will typically create anxiety about an impending absence of you. Buddy should be desensitized to those cues that can't be avoided during departure. You should repeatedly pick up the car keys, open, shut , and handle the door, put on a coat or pick up a briefcase so that Buddy habituates to these cues and they lose their strength in eliciting anxiety. Placing him in his cage, locking it in the kitchen, or opening and shutting the door are events that Buddy should be constantly exposed to when you're at home, during sit-stay and reward training sessions. Until Buddy has been desensitized to these cues, they should be avoided whenever possible during actual departures. Putting jacket and boots on in a different room, leaving a briefcase, handbag or key in the garage, and leaving through a different door while Buddy is otherwise occupied or distracted can greatly help reduce departure anxiety. Cues that are commonly associated with calmness, food, and your presence can be provided during departure to reduce anxiety. During departures, a TV, radio, or videotape can be left on, or Buddy can be provided with a favorite blanket to lie on. Some owners do not understand the principles of these techniques so that the dog is placed in a cage or a radio turned on only when the owner leaves, so that these cues become associated with anxiety and departure, not calmness.
Step 3) Greetings - Homecoming should be kept very low key and he should be ignored until he is calm.
Step 4) Obedience - Teach "sit", "down" and "stay" commands so you can begin teaching him to tolerate being alone.
Step 5) Teach the pet to be alone - phase 1 - This phase should begin with his staying for a very short period before accompanying you to various rooms throughout the home. Gradually, he should be required to stay for longer periods of time, until he will remain in another room for 30-60 minutes or more.
Step 6) Teach the pet to be alone - phase 2 - After he has been desensitized to the departure cues, you should practice short mock departures. You should initially leave for a very short period of only a few seconds to a few minutes. The duration should be shorter than the time in which it takes him to show signs of anxiety. Periods can be lengthened gradually as he responds without associated anxiety. The duration of departure should be lengthened on a variable schedule, so that he can't predict exactly how long you'll be gone.
Step 7) Exercise - Lots of aerobic exercise should be provided.
Step 8) Distractions - He may be less anxious when he has something to do while left alone. highly stimulating toys should be provided. New chew toys, food chews (pigs' ears, rawhide) or strongly motivating food pieces hidden in the toys, such as meat or cheese may get his interest. These treats can be hidden inside toys so that they are difficult to remove, in packages that he must open, or hidden under bowls around the home. In rare situations, having another pet will provide a playmate (or distraction) for a dog.
Step 9) Confinement - May result in increased anxiety unless he is already accustomed to confinement. Acclimating a pet to confinement should be done gradually. If this is not practical, anxiolytic medication (benzodiazepines, TCAs, SSRIs, buspirone) or D.A.P. may be useful.
Step 10) Punishment - Punishment should be avoided as should any other treatment modality that might cause anxiety.
Step 11) Hormones/Drugs - Dog appeasing Hormone (D.A.P.) may reduce anxiety, especially in primary hyperattachment disorders. Tricyclic antidepressants such as clomipramine (Clomicalm from his vet) are a good choice for chronic anxiety problems and have proven efficacy in clinical trials. Fluoxetine or other SSRIs may be an effective alternative. Benzodiazepines such as alprazolam and clorazepate may also be useful for immediate control of severely affected pets, especially those that have panic attacks. Other drugs such as barbiturates, propranolol, buspirone, and phenothiazines may also be helpful adjuncts to behavioral therapy techniques. However, on their own, they are rarely successful for treating severely affected pets.
Please respond with further questions or concerns if you wish.