I'm a lone parent with 3 DCs
When i had a serious spinal operation 5 Years ago my nearly 80 yo parents came down to care for me from their home 100s miles away and took care of me and DCs doe 9 weeks until I was fully mobile again
These days my parents need help themselves so are moving nearer me but they think they'll help me and I think I'll help them 
I do wonder if my teenagers would step over my dead body , ones already a uni student one is about to head off and one is still about to do GcSEs.
But my DCs teens/ some now adults do step up when needed if I groan and don't look like I'm sleeping.,, (on the floor!!
)
Infact my uni 20 yo son is planning to catch train back to help me when he knows I will need some help in middle of his term
If I couldn't manage, my neighbours, my friends and my colleagues would help me.
Never call in favours really- often help friends and neighbours when they need help, so I don't doubt they'd help me and on occasion when I've gone by ambulance into hospital and then needed to stay overnight, or longer, my neighbours and friends have helped out with younger DCs.