Good question.
Section 4.20.1 of the OHS Regulation defines “working alone or in isolation” as  “working in circumstances where assistance would not be readily available to the worker (a) in case of an emergency, or (b) in case the worker is injured or in ill health.” WorkSafeBC guidelines list the factors to consider in determining if assistance would be “readily available to the worker” for purposes of interpreting the requirement:

• Presence of others: Are other people in the vicinity’
• Awareness: Will other persons capable of providing assistance be aware of the worker’s need’
• Willingness: Is it reasonable to expect those other persons will provide assistance’
• Timeliness: Will assistance be provided within a reasonable period of time’

We know that there are other persons in the home. The fact that those other persons are adults suggests but doesn’t necessarily prove they’ll be capable of helping the worker. For instance, maybe they’re elderly or disabled. You just need to work through the criteria and figure it out based on the  situation to see if this particular telecommuter needs to be protected as a worker working alone or in isolation. Hope that helps. Glenn