My dad is having severe pain and bloating in his stomach&has had a double hernia for awhile and has high bp.was put on water pills. is this dangerous?

Watch for dehydratio: Basically, if stomach pain and bloating are preventing him from eating and/or drinking, the main concern would be dehydration, depending on the strength and type of water pills. Keeping his BP well controlled is very important as his age (64), gender (male), and risk factor (high bp), place him at risk of heart disease. Hernia pain could mask or mimic a heart attack. Go to er if any question.