I find this thread quite depressing at the lack of empathy for the aging process.
As the teenager is to the parent, so the parent is to the elderly person. In other words, we can't imagine how we will be when we are 67, and we swear we will do it differently.
However, Mintyy's PIL have enjoyed having the grandchildren to stay until this point. Now, it's getting a bit much. Maybe it really is getting a bit much, there's no hidden agenda. Now, while I'm sure when I'm that age, I'll be up for having my grandchildren for sleepovers, in reality I may not be. It might not be because I've given up, I'm not keeping myself fit, I'm not putting myself out etc. It might not be my fault at all! That is just the randomness of aging.
"Crikey, if I thought that I was going to go from a fit, working adult of 67 to someone who couldn't look after my 10 and a 12 year old grandchildren then I might as well lie down and give up now."
Well we all like to look on the bright side, but in reality some of us will be dead by then, or wheelchair bound, or just exhausted and struggling.
If I were Mintyy, I'd be asking what I could do to help make their life easier.
By the way, I'm 50.