I want to take 2 of my grand daughters to a music festival aged 10 and 6. We are hiring a motorhome. My son in law doesnt want the 6 year old to be away from him for four nights (even though he went snowboardng without her for a week recently) and so wont allow the 10 year old to go as it wouldn't be fair to the 6 year old. He is stepfather to the 10 year old - who is desperate to go. The 6 year old also wants to go but is less reliable about being away from her dad. I look after them frequently, seeing them every day and including overnight as I live next door and they like staying. I think my daughter and son in law are being selfish - am I being unreasonable?