Rowanwitch is correct. Pagan and Wiccan beliefs are based on nature and in harming none, but the belief in Summerlands is an individual thing - often envisaged as something like heaven, or a state of nirvana - reached by many cycles of death and rebirth. In this place, you can meet up with deceased loved ones, but again, there's no right or wrong with Paganism, and it's not an organised "religion".
Most examples taken from the internet or books on the subject, are just from the authors' personal point of view. There are so many variations that your best bet'd be to join like-minded people, and see if the group's ideas appeal to you.
Halloween's a good time, because this is the time when we believe that we're closest to departed souls than at any other time of the year, and there are many Wiccans and Pagans who'd be happy to expain this to you.
On Sunday, myself and friends will be celebrating Halloween - or Samhain, to give it but one name. It comes from a Celtic festival, loosely meaning "the end of summer".
We'll drink and make merry, but there's also a serious side to it, whereby we conduct rituals to enhance our - and others lives - or not, and to say goodbye to the "light side of the year" and to welcome in the dark months.
Summerlands is just a word to describe one part of our beliefs, but not used by all followerrs of the path
The sabbat, or festival is just one of many, and not everyone joins in with them - or any at all, but we follow certain rules or "laws" which we feel come under the natural laws of nature. We're generally a happy bunch, and your brother could learn much from how we live and what we believe in. Good luck to him.