Since your daughter is also a British citizen and you are concerned about her safety, it would be a good idea to reach out to the British government (foreign service) for help or the British consulate in Boston

https://www.gov.uk/world/organisations/british-consulate-general-boston

1-617-245-4500

Cemeteries and Arboretums are often dog free.

In particular, try Mt Auburn cemetery which is incredibly beautiful in the spring and fall (or with snow, I imagine)

Also Appleton Farms: Appleton Farms (978) 356-5728 https://maps.app.goo.gl/hpbXZS3QittvNVaaA?g_st=ic

The Trustees of the Reservation have a number of other sites that are dog free.

Here’s another example: https://thetrustees.org/place/boston-community-gardens/