I have a maltese x shi tzu x poodle (apparently) and she was my baby before the real one came along. I worried how things would go.

She did a lot of sniffing around on the day he came home. I don't think she knew what he was. She was scared of him up until about 6 months when they suddenly became friends. Prior to then if he tried to touch her she'd run off.

We'd get her to sit up on the couch while we held my son & let her lick his feet or on the head (like on the hair) & when he was older put his hand on her.

She still runs off from him if he tries to grab her, but they do get on well now.