My sister was told she has "surgical mumps" and was started on 2 antibiotics. is this an old fashion name for parotitis?

It may be: After surgery, some develop a rare but serious staphylococcal infection of the parotid gland which may cause post-operative fever. It is limited almost entirely to elderly, dehydrated, debilitated, and malnourished patients with poor oral hygiene. It appears in the second post-operative week and is often associated with prolonged nasogastric intubation.

Pretty Much: It is also referred to as acute post-operative parotitis. Parotitis is an inflammation of one or both parotid glands, the major salivary glands located on either side of the face. The antibiotic should clear it up.