Write in the delivery notes that the driver should contact upon delivery, that she appreciates them and would like to show her appreciation with a cash tip. If mom doesn't have a spare $10-$20, send her an envelope of tens ahead of time. Whether it's UberEATS or Instacart, the young strong driver will not be afraid of your mom, especially if she's wearing a mask! They'll text/call to alert that they're there, when she gets down the stairs she negotiates with them to carry the food up. Or give your number and coordinate once the driver contacts you to let you know they're there; call mom, tell her to let the driver bring the groceries in and give $10-$20. One of my sons went away to university just before turning 16. He was too young for the dorms, too young to drive to the store, had to get creative making sure he stayed fed!