@AlunWynsKnee I've had similar worries - my 9 year old has ASD so would not cope at all being away from us, and no family under 70 who could help.
So, I've done what I can to prepare sensibly - its unlikely DH and I would be that ill both at the same time, but in the worst case if we were and unable to get out of bed, then I've prepared stuff for DC that they can cope with.
I've filled a low kitchen cupboard that they can reach with fruit shoots, cartons of juice and UHT milkshakes. Plus cereal bars, crisps, crackers etc. The fruit bowl is within DCs reach and always full. The fridge has cheese dunkers, yogurts, packets of ham and billy bear. All stuff that we use normally anyway, just a bit extra. Its not ideal, but in a worst case scenario, a couple of days of eating cold food won't harm dc.