I'd just try to be patient and coax him through it, carrying along a treat or squeaky toy to use to divert and hold his attention on that as a stranger approaches and passes by until he begins to feel secure without his big buddy along. Once he's allowed to see that nothing bad happens but in fact he gets a treat or his favorite squeaky toy sounded when a strange person or dog approaches and walks by, in time he should come to think that someone coming is a very good thing and brings him a tasty tidbit or a fun squeak of his toy.
Reinforcing his self-assurance by keeping him busy with life-enriching activities and things should keep him focused and working through his loss of his big brother and help him deal with the loss.
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |