It's such a relief you seem to have a good vet help you.
Yes, your mom is correct about antibiotics. There is a probiotics in packets that we used in our chick water that I'm sure would be ok for adult hen consumption. It's what we used for an indoor segregated hen that happened to be on antibiotics. I'm sure any chick or hen probiotic brand will be fine. Ours dissolves in the drinking water so obviously our hen would be segregated cuz she should be the only one drinking antiobiotic solution apart from the rest of the flock w/her own separate probiotic drinking water.
Again, a mirror is a great companion for a segregated hen. Our bumble Dominique would nibble the mirror & look at herself in it, prance in front of it & snooze next to her reflection ~ mirror is a great babysitter! I found other owners say they do the same thing.
I'm sure you all will do what works for you. Don't feel frustrated about the time it takes to heal bumble. Larger hens are more prone to it than smaller birds. After years of regular size hens ~ for ourselves ~ we went back to an all Silkie flock cuz they lay decent size eggs & ~ apart from going broody often ~ we've had less health problems w/ Silkies plus they are very gentle birds compared to larger breeds. Silkies are very much chickens like any other chicken just different in temperament & broodiness. We all have different breeds for different reasons
As for tablets I'm no help. I have read owners have a difficult time getting their ckickens to take tablets but I never had to deal w//tablets. My Silkies have always been prescribed liquid antibiotics directed by dropper. I had one Silkie years ago would drink the medications out of the palm of my hand. The vet tried to show me how to put the dropper/syringe down her proper esophagus ~ I took the syringe out of his hand & squeezed the liquid into my palm & my Silkie lapped it up w/gusto ~ he had never seen a chicken do that before! She drank children's no-iron Poly-Vi-Sol vitamin liquid out of my palm also.