Hi Silkcut, sorry to hear about your Mum's foot.
Wondering whether the nursing home is authorised to formally discuss medical treatment with you, strange as that seems.
The NH my stepfather, who died in July, was in had a contact list for alerting guardians and/or family. The first on his list was my Mum as his next of kin, then me, my husband, SF's son who lives interstate etc. The NH policy was to start at the top of the list and keep going until one of us were contacted. They were required only to alert one person on the list.
From your past posts I wonder if a social worker is the first point of contact in your mother's records for legal reasons. If so, the NH would have absolutely no right to tell anyone, even a clearly dedicated, devoted and loving son such as yourself information about your lovely Mum's medical history.
Would it be worth checking with SS, when the distress and worry of the current situation have abated a little, what the contact protocol is, and suggesting a review?
Good luck with this Silkcut, patience is the hardest thing in the world to come by when we're worried with good cause, but I'm hoping it comes your way in spades, Toni.