Hi welcome to HCM
I can understand your concern for your dad's stomach pain,
vomiting and mild
fever.
Dear, The apparent cause of your dad's suffering is Ham , he took for lunch which he could not digest and created gas in his stomach and caused him all the suffering .
For your info, you need not worry . Vomiting and mild fever are natures boon to help you to move towards road to recovery by eliminating toxins from your body .
..He will be well soon .Give him lemon juice in glass of warm water with a pinch of salt & black pepper with half spoon of bishop's seeds -ajwain .It gives instant relief from gas ,stomachache and
constipation as well .
Repeat this again after two hours if required .
Proper rest ,hydration and balanced diet containing fruit , veges , soups
&juices are good to restore better helth
Avoid fried ,fast foods and other indigestibles .
If problem persists ,consult your physician .