Maybe I can help, HS;
I don't know if your S and/or BIL have been here or read any of the infromation about infidelity and what the right way of recovering from it is, so I would suggest this as a good place to start.
I'll post some links at the end of this so you can find thigs more easily.
But, as far as immediate help, the basic premise is that relationships should be based on:
[list]</font></li>[*]<font size="2" face="Verdana, Arial">Protection - avoiding being the cause of each other’s unhappiness </font></li>[*]<font size="2" face="Verdana, Arial">Care - meeting each other’s emotional needs </font></li>[*]<font size="2" face="Verdana, Arial">Time - giving each other our undivided attention and </font></li>[*]<font size="2" face="Verdana, Arial">Honesty - being totally open and honest with each other.
Now your S and BIL have several great advantages already; first, the A has ended. Second, he's admitted it, and had said he's sorry, and third, he's trying to recover his marriage. Believe me, they are more than half-way home!
Sounds to me like perhaps he does not realize what he should do in order to treat your S better, how to recover trust, how to improve the M; and if he's willing to learn, this is a good place to start.
How To Survive Infidelity We're very sorry to hear about your situation, but have faith; you've come to a good place.
MarriageBuilders has numerous resources and information which will help you. Start by reading Dr. Harley's Basic Concepts here:
DR Harley's Basic ConceptsAnother good resource to get you started is the Q&A section of the web site, where you'll find articles and guidance on many different topics:
MB Q & A Columnsas well as the articles section:
MB ArticlesIn these forums, you will find many people who are or have been in your sister's situation, and will help her through this, give you ideas and encoragement.
There are also Notable Posts, which will guide you in many areas:
Notable Postsand the Reading List, in addition to Dr. Harley's Books:
MB Book List w/LinksDr. Harley's BooksWelcome; we're sorry you had to come here, but we're glad you did!