Helos land all the time without a fire department standby. Typically, a fire department response for a helicopter standby is a department or county level procedure.
In Maryland, most counties and fire departments DO have an engine stand-by for a medevac landing, but the Bel Air VFC has a number of pre-determined LZs in their district where the medevac will land without the FD standing by.
Many FDs that respond for helicopter stand-bys routinely become lackadaisical, park too close to the LZ, don't don PPE, and wouldn't be of any real assistance in the event of an aircraft mishap.