There are some good minty anti-gas pills over the counter. You chew one and it works quickly. That is presuming we are not dealing with an allergy.
Massage the calf muscles of both legs - grip the leg(with both hands) and release while moving up and down the leg.
Sit in vajrasan position after eating, and do anulom vilom pranayam, to get extra oxygen into the body to aid digestion.
Hi and welcome to the forum
It is very nice of you, to be concerned with your grandma's health.
First she needs to identify the offending food(s), if that is what is causing the bloating, as there are a number of things that may contribute to or cause bloating.
Intestinal bacteria, gas producing foods, swallowing air, etc.can cause bloating.
Sometimes, large pockets of sulphur-bearing gases cause the gut wall to stretch beyond its comfortable elastic limits, that's when we feel that uncomfortable blowing up and expansion of the abdomen.
Avoiding swallowing air, food elimination diet and avoidance of gas producing foods
may be of help. Please research on your own to explore these options further.
There are natural supplements also available that address bloating issues.
If you need more info please post again here.
Blessings
Nikodicreta