Brandy and other alcohols have traditionally been used as ;gripe water' - to stop e.g. children forom complaining, as an active placebo. "Mommy's going to give you some medicine and everything will be better."
all alcohol --brandy included-- disrupts the mucous membrane lining in the stomach and contributes to ulcers. I imagine if anything it would exacerbate a stomach ache.
Ginger works well for me, although there is an inconclusive evidence base, if you're looking for a simple home remedy.. don't have lots though as it can irritate your stomach in large quantities.