For your grandpa, someone could rig up something with bells to let someone in the house know when he moves much. And we used a baby monitor to listen to my FIL no matter what room we were in.
I'm glad you had the meds in the house - I keep some for my really, really bad days too. I hope to not have to use them again though!!
You are NOT a failure to your family - it's just very unfortunate timing of things. You didn't
choose to be sick!! And he didn't choose to need this kind of care. Do what you can from home and don't beat yourself up - that's adding to your stress!