Just to chime in - my son is 2 and has been hospitalized twice already for 6-7 days at a time. My husband and I both work full-time, have 3 kids, live an hour from work/hospital and have limited vacation. I happen to work at the hospital where my son goes so I have the flexibility to run back and forth, but neither my husband or I have enough vacation time to be there 24/7. Now, saying that, we always tried to have grandma up there when we weren't there or child life therapist entertaining him and one of us always stayed the night - HOWEVER, I hope noone would judge me if I had to leave my son to work. Because if we aren't working, we have no insurance and bills don't get paid. Plus our other 2 kids have needs as well that we can't forget about.
If I didn't have to work - you bet, I would be there 24/7 because his health is our absolute priority. But, we also have a wonderful relationship with our pulmonologist and he would never do anything without consulting us - unfortunately, I missed his daily visits several times while I was at work, but he would either call me or grandma would let me know what he said. Also, an advantage to working at the hospital - everyone knows me and Jack so they really look out for us. Plus our children's hospital isn't as big as some others because it is a CH within a hospital - but awesome, personalized care - very doubtful we would encounter another CF kid at the same time.
I would never leave a 2 year old, but I probably wouldn't hesitate leaving my 8 year old for a while if I was comfortable with my doctor and hospital. My 8 year old is very mature and would be fine by herself for a while - I'm not talking whole day or anything, but a few hours, yes. Especially when you have trained child life therapists to help entertain them.
Either way - hospitalizations are hard on families. Earlier this year, my husband and I were both stuck at the hospital for 2 days during a winter snow storm and missed our 5 year olds birthday - talk about heartwrenching! I know it totally upset me more than her, but gesh - you just can't leave siblings out.