Dear friend, welcome to HCM.
if your partner can walk without pain / limp, fracture
is unlikely. especially if the bony shin feels uniform to touch in front.
if you say there is a painful roundish swelling, it could be soft tissue trauma/ or bleed (hematoma
if there is nothing else happening and the ER doc felt there is no fracture, it would resolve.
if you are anxious or it is not settling, pl. get it evaluated from another ortho doc to look for the fracture or soft tissue injury
I think distantly I can offer this much advice.
thanks and wish him good luck.
pl. keep me informed on the progress.