In my experience, there are three basic types of grandparents of unschooled children : those who need no converting, because it was their own style of parenting; those who were somewhere between sceptical and incredulous at first but are en route to being on board now; and those who think it is a damaging and irresponsible way to raise a child. For now, I'm going to tackle the last variety (figuratively speaking, no grandmothers were harmed in the making of this article!) as they can be one of the greatest hurdles on the unschooling path.
So how does one convince the unconvinceable? Change the mind that's been set for an entire generation longer than your own? I'm sure you've heard this saying before : "How do you eat an elephant? One bite at a time." This most definitely applies here. Rather than attempting to explain the entire philosophy over a tense cup of tea, take the foundations of unschooling and apply them, in the same way you have with your children. While it is true that they simply need to respect your parenting choices, it'll be much easier for everyone if they understand why you're making those choices.
Take one thing at a time: Don't expect them to be fully on board with it just because you are, and don't bombard them with lots of things they need to do differently. You probably started your unschooling journey with one thing you wanted to change, and this is no different. However, rather than starting small and working up, you may find it more effective at calming the waters if you start with the biggest cause of tension between you and your parents and/or in laws. (My guess - food, bedtime, or long hair on a son/messy hair on a daughter.) If you can effectively remove this frequent source of unease, you will find contact with them much less stressful, and hopefully it will follow that the lines of communication are much more open in both directions.
Talk to your children : Remind them that you are all working towards a new way of being, and that Nanny and Grandad need time to learn too. Also, that while you are living it all the time, they only get to practice it when you visit each other, and so they aren't getting as much time as you are. Encourage older children to speak up to help protect the rights and feelings of younger siblings as well as their own, and in our family the addition of a conspiratorial wink has taken the sting out of the words of others.
Respect : It's frustrating as hell when all your hard work at encouraging your children to choose their own clothes, or eat instinctively, is at risk of being undone by a seemingly thoughtless comment. (This is why the reminders to your children that Nanny and Grandad are still learning are so important.) Don't become a hypocrite, however hard that may be. Continue to model respect and patience towards your children's grandparents as you gently remind them that you don't believe that is the best way to approach the subject. This will pay dividends in the long run - your children are always watching and listening, even when they're in the other room watching Minecraft tutorials on YouTube.
Be honest. With everyone : You'd like your children to grow to always be able to have open, honest, but tactful and thoughtful conversations with you. You may well feel this is not the case for you and your parents. Well, now's the time to start! If your children have pushed your buttons all morning and you arrive at your mum's for lunch with your sanity hanging on by a thread, don't hide it. But tell her the WHOLE truth - that you stayed calm and reasonable, and handled everything fairly well, and that on reflection, you're actually quite proud of yourself. Remind her that you're still finding your feet with it all, and that their support is really important to you. If you don't feel that this will be an option, cancel that lunch. The last thing you need after a hard morning is to be on edge all afternoon. And tell her, tactfully, why you'd rather do it another day :
"I'm sorry to have to cancel so late, but I'd prefer to come for lunch another day. We've had a difficult morning and I could do with staying home to relax this afternoon."
This may well open up a discussion as to why you don't feel you could relax there. It may well be a hard one to have, but it's necessary and usually positive in the long run.
Thank them for what they do : They made dinner for you all, and your children didn't eat any vegetables or say thank you. Your mum pulled that face, and your dad cleared the table a little more abruptly than usual. Thank them both for a lovely meal, then once the children are safely out of earshot, thank them earnestly for not commenting on their eating habits, and for not demanding a thank you from them. Add in a quick reminder of why it's so important to you, how much you value their support, especially knowing how hard they are finding it to get to grips with, and that you can see how much they love you all through the effort they are willing to put in.
There are no quick fixes in Unschooling. We know this. The same patience and dedication we give to our own journey with our children needs to be applied to that of the journey with our parents, our aunts and uncles, maybe our own grandparents, and siblings. Rather than reserving our unschooling head for our interactions with our kids, we need to use that way of thinking across the board, changing the way we interact with everybody; and slowly but surely the effect will trickle through the years of conditioning, producing an ever growing stream of conscious unschooled thought.