I agree with Cindi, it depends on your brother and his wife's personal preferences. If they want nightlife, social scenes, convenience, I'd recommend Emeryville, Berkeley, North Oakland, Rockridge. If they want quiet, more suburban communities, I'd recommend Berkeley Hills, Oakland Hills, Albany, El Cerrito, Fremont, Hayward, Union City.
Berkeley, baby! Great restaurants, cool shops, culture. Diverse and eclectic mix of students, professionals and hippie leftovers from the 60's. Close to SF, but prices are lower and with less congestion. There's the legendary family-owned Berkeley Bowl for the best produce selection in the state - and at reasonable prices compared to that other big food market in the recent news where the CEO went to the online message boards to bash his competitor before making an offer to buy them :)
Really great restaurants in both Berkeley, Albany and nearby Rockridge (Oakland), unique boutique shopping on Fourth St, varied styles of housing (this ain't the 'burbs!) and lots of trees keep it real. Birthplace of Peet's coffee, Tilden Park for hiking, biking, walking, the UC Campus.
It all depends on price range and lifestlye. Are they looking for nightclubs, shopping, restaurants? Condo, townhome, or single family home? A good Realtor will interview them, find out their needs, introduce them to various communities, then work with them to narrow their choices on their ideal home.
The East Bay is a great neighborhood for young couples. Berkley, North Oakland, Rockridge area is one of my favorites it has an educated population (lots of Berkley grad students) with lots of shops and restaurants. It is very close to BART so that commuting is very easy.
Check out the link below it is to the Heat Map for Oakland the zip of the neighborhood I am speaking about is 94618
The best city in my opinion is in the south East Bay - Fremont. Depending on where your brother and wife work, this may be a great option for them. Fremont also boasts some of the best schools in the East Bay - in the Mission Hills. This may not be a concern right now - but you never know. Values are also well supported there by all the high tech job sites from Fremont, Milpitas and into Silicon Valley (San Jose). As an ex-Fremontonian - I highly recommend this town.
You might want to check Hayward. It has BART to the City, easy connection via enhance San Mateo Bridge (more lanes) to the Peninsula, but most importantly, a lot of new development and condo conversion. Please describe their requirements closer and if the area might be suitable - I will post more information. The bottom line, they can get a nice place in Hayward area below $300,000.