There are many options for your daughter and her family in that area. The Oak Square area of Brighton has many great apartments in 2 family houses, as does the Newton Corner/Watertown Square area which is a short distance away. Both areas have access to public transportation (buses) that your daughter can use to get to St. E's. Also, that area is close to the Massachusetts' Turn Pike (Mass Pike), which makes for easy commutes into and away from downtown Boston.
I have lived in Oak Square and Newton Corner, and I would recommend Newton Corner, but that is just opinion. My reasoning is the convenience to restaurants and supermarkets in the area.
There are some nice options in Brighton and around, but before you start looking get pre-approved and than an agent. Watertown does have some nice condo conversions and it is bordering Brighton, but again your price range is the key.