Dear Arlene,
How old is your dad? I know that the word 'sepsis' means infection, so your father's doctors have already had to meet the challenge of fighting an infection while he was on treatment. How did your dad respond to antibiotics?
For most people there is a very low mortality rate for ASCT. As far as I know it is possible to treat infections with antibiotics even when someone's immune system is suppressed. I've had a transplant and coped well even though my lung was accidentally punctured while my line was put in, and I guess that this could have made me more susceptible to infection. I think the questions you need to ask the medical team could include whether there's any reason why antibiotics couldn't be given to your father after transplant or whether they might be less effective for him than for other people.
I'm sure that if the medical team are concerned then they would pay very close attention to your father and they wouldn't send him home too early.
Good luck,
Eva