We had our estate plan drawn up a few months ago, so a little before then we were looking for a lawyer. We asked all our friends and acquaintances who we thought might have been in similar circumstances if they had a lawyer. One particularly well-connected acquaintance (he is a former city councilman) gave us a good lead.
Fortunately for you, finding a decent estate law attorney is not that difficult. The cost is low, and you aren’t fighting some bastard in a horrendous lawsuit, which really sucks. My lawyer cost about $300 to draw up my will.
Lawyers like wills, because as a rule, they are fairly simple and the basics can be drawn up by a paralegal, who’ll do all the legwork. That way the lawyer can just review it, make sure it holds up and it’s easy money.
My Wills and Trusts Professor told me how to make sure no one screws with your distribution of your estate after you die: give it all away while you are still alive.
Remember, your half-brother is evil (half evil or fully evil?) and no matter what you do in writing, he will manipulate your remaining relatives into getting what he wants. That is the nature of evil. You did say he was evil. If you give all the stuff away now, even if they do give it to him, it will have been theirs to give first. Also it will have the advantage of your family treating you super extra special because they will interpret your giving everything away as caused by suicidal depression.
Personally I don’t have a will because I want my brother and sister to fight over the really cool stuff and who has to throw out the tons of hoarded junk. My brother has claimed dibs on my faux antique bar globe. My sister, however, is a federal cop and can bet the crap out of either of us. Wish I was going to be alive to see that ass-spanking.
The problem with giving away one’s house while still alive is that one would dearly like to live in it. 
That’s most of my assets, aside from little things like jewelry bequests.
One thing you should be aware of is that beneficiaries on bank/investment accounts pass outside of probate. People rarely think about that or update those beneficiaries. After a divorce, people will change their wills, but forget about the beneficiaries on their bank accounts. Make a point of checking them when your circumstances change, or change them all so that the proceeds pass into your estate (thus subject to your will).
Zsofia, I sent you a private message.
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