does it have tags on? hopefully that will help for a speedy return..same with a dog license (if they have them in ireland)

contact your animal control officers & let them know the dog is missing..same with local police & animal shelters...this way if they come into contact with him then they will be aware it is a pet & not a stray.

i wish you good luck in finding him...with the weather getting colder i hope he is found quickly...it isn't a good time for any pet to be lost & alone...plus with vehicles & such...there are many dangers out there...

maybe you can get someone to help you create some sort of a containment system for them so that both he (when he returns) & his brother can be safe. pets deseerve to be indoors by a fire & warm & toasty...with their pack members...not lost & outside.