One’s written and properly executed Last Will and Testament is assumed by the law and by courts to be the written expression of the testator’s intentions regarding his or her estate. Even when its clear to the family and others that the written language of the Will isn’t what the testator intended, it’s very difficult to overcome the actual terms of the Will as it was written. Here’s an example in a Florida case where the testator used a DIY Will form that she purchased to save money and, as a result, two nieces inherited her property instead of her surviving husband.
I always recommend that my clients use an estate planning attorney to draft and implement their estate plan. It’s just not worth the risk, not to mention the family torment, that may result from making even the smallest of mistakes.