We are now in a similar-ish situation with my husband’s parents as you describe. They are mid-70s, we were older parents and have a nearly 3 year old.
They do ok really - still able to get out and about themselves, book their own appointments etc. FIL is fit as a fiddle and walks miles every day. MIL less so, but manages the garden and does a gentle keep fit class for older people, plus is on some committees/ charity things.
They do also help us, some babysitting here and there for example - though we try very hard not to ask them often as it always comes with such a performance afterwards of how exhausted they are, how it’s too much for them, she’s worn them out etc etc so it has to be quite minimal - I’m happy to make alternative arrangements but they get offended by that so seems a bit can’t win.
However Covid definitely made a huge difference - no particular requirement to shield beyond age group but just really dented their confidence. It’s since then really that all we ever seem to hear about is how old they are, how it’s not for people their age, older people like them can’t be expected to do that, when you get to their age - it’s pretty constant and at odds with how much they can and do do - but it’s also becoming a bit self-fulfilling I think. They’ve talked themselves out of some really lovely things on the grounds of ‘it’s too much at their age’ - which seems a shame as they actually manage more complex/ challenging stuff but it’s just their perception of what they can/ can’t do.
The requests for IT/ tech support from my husband are getting more and more constant - there’s a phone call at least 3 or 4 evenings a week ‘your dad has clicked on something and the screen has gone black’, ‘I’m trying to send a picture to Jean and I can’t do it’, ‘it’s saying we need an update’ etc. They both increasingly monologue at us about their pet subjects (to be fair this was always the case with FIL and I suspect there are other factors at play there, but MIL is doing it more and more). Struggle more and more with banking - lots of rants about how unfair it is to make older people do it online and they refuse to do it so DH has to do anything like that for them. He’s off work today but has already gone to help them by taking some stuff to the tip and then they want help booking a flight - I feel for him as he’s had about 3 hours sleep as DD was up so much struggling with the heat.
MIL doesn’t drive and FIL increasingly frets about his car being damaged so he doesn’t like to much, which means we’re getting the odd request for lifts too - trying to hold firm on boundaries there although will do it if it is convenient for us.
They have another grandchild who lives abroad but they’ve never met because they’re too old to get on a plane apparently - although looks like that might be finally happening now (hence flight booking) - we will arrange assistance for them at the airport, and they want help finding insurance etc.
My aunt is a good ten years older than them - and granted is a bit of an anomaly but still worked, travelling all over the world right up until covid. She’s still has such a full and active life now - puts me to shame. But when she comes up in conversation my in laws are always saying things like ‘I suppose she won’t be wanting to do X, we’re the same, it’s too much when you get to our age’ - and I think she’s got ten years on you, and yes she is still doing X and Y and Z too. My mum bless her only got to 72 but until that brutal illness she was the life and soul, more like someone in their 50s/60s - so I find their insistence on acting like they’re 90-odd a bit harder to understand.
They actually did an awful lot of caring for FIL’s parents - his mother only passed away a few years back at 96. She didn’t need much help physically but anything practical from shopping to bills to the house etc they had to do for her - apparently this wasn’t so much an age thing she’d always required an awful lot of support throughout her life.
I do worry what the expectations will be on us going forward, particularly after all they did for their parents (although they got a great deal of practical support when their own children were little too, which we do not with us all being so much older). DH’s brother lives abroad so it’s only really us around.
Selfishly I feel I’ve done all the caring I’m prepared to do really - my dad had a stroke when I was 15 and was severely incapacitated at home for 8 years - my mum took on most of the burden obviously but it impacted me, then my mum got cancer and I was caring for them both around the time I was doing A-Levels, then in my thirties I dropped everything to care for my mum when she became terminally ill - right decision and I’d do it again for her, but I was single then. I also spent a few months abroad and away from DH supporting the aunt mentioned above after she had cancer surgery - again before DD. I now have a very full on toddler and am trying to get my career back on track from various interruptions and I just don’t feel up to taking on that role for DH’s parents, though will of course support DH to do whatever he needs. Will have to see how things go and cross that bridge when we come to it.