My parents and little brother are coming to visit and stay with us for 3 weeks this summer (yeah, can#%92t wait [

])!
Here#%92s the problem: they cannot take their dog “Blacky”. They don#%92t want to put him through a 9 hour flight and he is also pretty picky about the dogs he gets along with so we wouldn#%92t know if he#%92d like Joey or not.
They decided to board him in a kennel while they are gone. My dad is a BIG worrier!!! A little background info: they adopted/rescued Blacky last March from an organization in Germany that rescues dogs from the streets of Hungary. He#%92s a very good dog (about 3 years old, neutered, no separation anxiety, he stays alone for about 4 hours a day (he#%92s not crated) and is a perfect little angel while alone. The only problem is his resource guarding and he does have leash aggression. Unfortunately there are no places to take him off leash (he#%92s a hunter and catches mice even while on leash, yuck

) so they can#%92t let him meet other dogs safely to see if he has dog aggression while off leash. However he has met my grandpas dog and they get along fine (they don#%92t play but peacefully co-exist)!
My dad is worried that if they board him for 3 weeks he will freak and not “like” them anymore or have separation anxiety after the stay at the kennel!
What do you guys think about that? Any experience in a case like that?
This place they are going to take him has been very well recommended to them. It#%92s a dog training academy but they also board. He would have his own kennel but also has the option of coming to the owners house (that#%92s if he gets along with the other dogs, which we don#%92t know). I don#%92t know how much 1 on 1 time these people provide to each dog.
Would it be a good idea to take Blacky there a few times over the next 2 months (they are coming here July 29) to get him to know these people. Maybe have them give Blacky treats so he thinks it#%92s a “great” place to go????
Any advice would be greatly appreciated! My parents are really worried, he#%92s their baby and they want to do what#%92s right for him!
Oh, here's a picture of the little stinker!