My dad, 44 year old male 3 hourse (3 or 4pm) ate a lot of fried pig skin and when we came home half hour ago, he drank a lot of water and complained about headache, he burped and said the burp is sour and said and vomited later on. thank you?

Overeating probably precipitated acid reflux that may have induced vomiting. It should resolve on its own. If you father is overweight, it would be prudent to lose weight. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get Flu and Covid vaccines.