Update: Thanks everybody for your suggestions. I started with baby steps and it's gone great! We are now doing short, separate walks without any issues. I am so proud of both of them, especially Xavi, who was my biggest concern.
I live with two galgos. I adopted the first one just over 2.5 years ago. He was extremely traumatized and terrified of everybody and everything. Treasure the greyhound lived with us, also, but she passed away a year later.
This past April I adopted Xavi, galgo number two. Iker chose him and they have been inseparable. Iker has gained so much confidence that sometimes it's hard to believe that he is the same dog. That's not to say that he doesn't have his moments, especially when Xavi isn't around. Xavi doesn't like being away from Iker, either.
Should I start separating for short periods of time, such as separate walks? Would that help to build confidentce when arlone, or might it result in Iker regressing to old, traumatized behaviours?
Thanks.