Congratulations on your brother getting back online. Now have your brother run, not walk, to the nearest store that has uninterruptable power supplies and get enough of them to handle all of his computer equipment, including his DSL modem. Not only does a UPS protect the equipment against power sags and outages, but it can even isolate the equipment from some lightning problems. Note I said "some" problems. I had a lightning strike on a metal light pole three houses down, and the radiated electromagnetic pulse was picked up through my house wiring and killed a bunch of my equipment. I wish I were making this up-it was VERY expensive, since so many different things were damaged. My TV, stereo, 56K modem (a part inside it literally exploded!), two surge suppressors (the surge actually charred some parts, but they had very odd warranties, so I couldn't collect), and a digital answering machine. The computers were on UPSs, so came through fine.

Today I have everything I can run through a UPS. The prices are coming down rather quickly, so they are often a great deal, too! I really strongly recommend them.