I get what you're saying OP
My DS paternal grandparents are older (late 70s and early 80s). His wonderful grandmother on that side is an absolute rock, they both love DS, thankfully DS has had the chance to form a real loving bond with both his grandparents on his Dads side but I do worry about their age, health, wellbeing etc. They e not been able to do the physical things with DS that THEY would have like either.
My parents are early/mid 50s... we go on days out, for meals out, holidays abroad together, my parents are very involved in my day to day life and therefore my DSs etc...
BUT - I'm KNOW that my DS will always love and adore his paternal grandparents just as much as his maternal grandparents for the time he spent just sitting with them, being in their cosy farmhouse, hearing about the old stories, being tucked up by his beautiful white haired Nan, hugged and kissed by his "unaffectionate" grandad.... the list goes on!
It's different, but it doesn't make their relationship any less special, magical, important if the effort and time is put in.
Visions of my Nan taking her white hair down from her bun while I was snuggled in her bed waiting for her to come cuddle me still bring a smile to my face and a tear to my eye