We also had to draw a hard line in the sand with my ILs. Sam and my FIL have such a wonderful connection, it really is unexplainable how close these two are -kindered spirits. FIL traveled with us to pick him up and they bonded quickly and easily.
The problem happened when we got home and they wanted Sam to sleep there, sit on Gpa's lap while he ate, all no-nos for attachment and we were struggling with indiscriminate attachment already with him.
I finally just pulled him away and we had to be "busy" a lot when they wanted to get together. They were not happy with us, but I think now they understand. I also made it clear that we conforted him, we fed him, we co-slept with him or put him down for bed - and only us. Whenever they acted inappropriately, I picked him up and removed him from that situation. It was hard because I also had the baby and because DH wasnt really on board with AP at first. He thought I was over reacting.
Christina