Do they need software? Presumably the volunteer firefighters 30 years ago didn’t have this and did fine. Plenty of volunteer organizations are built on Airtable or some spreadsheets.
The software can quickly load box data (PDFs of hydrant locations and building details), as well as provide route mapping for individual at their location compared to call.
Additionally, every volunteer has a somewhat modern smartphone in my rural/suburban area. Pagers are not in huge demand anymore.