Campbell Its interesting the whole baby-boomer generation thing - and am about to generalise madly here. But, I'm going to go back to work soon and mentioned this to mil, her first comment 'I hope you won't want more childcare
'd when I read this 'generalisation', but would agree with an extended version : that GPs fall into two distinct camps - the 'engaged' variety, or the 'disengaged'
I adore having my grandchildren. In fact have just had a wonderful long weekend with the youngest (one year old) who ran me as ragged as only a toddler can. Reminded me that I can still giggle at 6am. And keeps me young. I would have any one of mine, at the drop of a hat.
His other grandparents adore him, live roughly the same distance from him, and have never had him to stay. SIL is their only child, so focus for them is solely one directional). Its not about love - they love their SIL, seem to love my DD and could not be more proud that they have their first GC. They are simply not child orientated, and do not cope well with looking after him even in his own home.
The difference applies also to how they regard "support". I have always managed work plans, or socialising, to fit with whatever my children have needed in the way of family back up when their children were young; and have actively changed plans at the last minute to do that. DDs inlaws would give them anything they needed, but are also prone to phone at the last minute to say they have changed plans and won't be coming and would never consider changing their own plans to assist.
Its a priorities thing, not a love thing.
For what its worth, OP, I am in my 60's and have no issues with running around after the GC's. I love it. My MIL took my eldest on a three State driving trip in America, at 67, and took my youngest on a week long trip swimming with dolphins at 71. No issues, and she spent months showing the boasting books of holiday pix, to anyone who would look !!
In your shoes, given everything you have said about the situation, the latest statement seems totally out of character for them, and I think I would be wondering if someone is hiding an illness?