Hello All,
I will appreciate any sane and useful advice on this. I have two sons. Elder is 4 year old and younger is 2 yrs old. I love both my sons a lot and as a young father I spend lot of time with them. Every now and then my inlaws come for visit. When they are here things go haywire. My elder son does not spend any time with me. My FIL sticks to him a lot. Also my son calls him daddy too. I have taken up this matter with my FIL and asked him to remind my son to call him Granddaddy. Its one thing to play with children but its another to stick to them. My FIL never leaves his side, he even lets him sleep with him. Luckily we don't invite them to our house too often but when they are here its like hell for me. Am I just being insecure ? Or my FIL's behavior is way out of the ordinary. We are going on vacation for a week and I am not comfortable with leaving my sons with him due the affection he showers on them especially on my elder one.

Make some strict rules, and let them know if they don't follow, then visits will be restricted.
What does your wife say, has she spoken to her dad.

I had a similar situation with my FIL. He has 5 grandsons, and 5 granddaughters, and out of all of them, he chose to very blatantly favor my oldest son out of all of them. Not only did it make him feel uncomfortable, all of the other kids noticed and they were upset about it too. He would come over and bring special treats for the oldest and none for my youngest. Stuff like that went on all the time. I was feeling very uncomfortable about it too. My husband and I and the rest of the family finally sat down with him and told him if the behavior continued, he wouldn't be able to see ANY of the kids anymore. At first it didn't really work, but when he saw that we were sticking to our guns things slowly started to change. Now, for the most part, he's fair and equal with all of the grandkids. Also, this may be a touchy subject, and I mean no offence whatsoever, and keep in mind I am definetley NOT an expert, but when this was going on with my son, I did a lot of research about molestation. He was showing, what I considered, classic signs of luring a child in. Turns out I was wrong, but when it comes to your kids, you can never be too careful. Once again, I am not an expert by any means, I really hope I haven't offened anyone.

It may just be he is more comfortable with your older son since he is more capable of interacting. Maybe let FIL know that little "Stevie" (the 2 year old) would like to spend sometime with grandpa too. Do they get to see the boys very often? He may just really enjoy spending time with him. Maybe he regrets not spending much time with his own kids and feels a need to make up for it now... who knows.

Does the attention make your wife uncomfortable as well? Maybe she could have a chat with him about spending more time with the other one because she knows "he wouldn't want to favor one over the other and cause any hurt feelings."

If the sleeping situation causes you concern, simply have it be a house rule that the boys have to sleep in their own beds... if you want to avoid possible hurt feelings or causing more discomfort, just say they sleep better that way and are very cranky when they don't get a good night's sleep. Or he won't sleep well on his own after he has had someone with him so you want to avoid that habit early on. Ask grandpa if he would like to read him a bedtime story and tuck him in, but then say goodnight. This can carry over to when you are away too because, after all, "you and your wife could have a nightmare with bedtime if he got used to having someone to sleep with and then didn't once you got home."