I'm on the other side of this, meeting a friend two or three times a month to play Go and giving him a three stone handicap on a 13 by 13 board.
Sometimes I play a move with a huge, but hidden threat behind it. If he plays elsewhere instead of answering locally, I get to play a clever sequence and capture some stones. I could just wait for the blunder and win. Instead I give a quick lesson in tactics: here is my plan, if you want to play elsewhere, your move needs to have an even bigger threat behind it.
He is learning, and now I face my clever moves being player against me. This makes it harder for me to win (it is about 50:50 with the handicap), but also more fun for me to play.
You could ask your spouses brother for a "teaching game" or a larger handicap, or a bit of both.
Sometimes I play a move with a huge, but hidden threat behind it. If he plays elsewhere instead of answering locally, I get to play a clever sequence and capture some stones. I could just wait for the blunder and win. Instead I give a quick lesson in tactics: here is my plan, if you want to play elsewhere, your move needs to have an even bigger threat behind it.
He is learning, and now I face my clever moves being player against me. This makes it harder for me to win (it is about 50:50 with the handicap), but also more fun for me to play.
You could ask your spouses brother for a "teaching game" or a larger handicap, or a bit of both.