About the solution
Conker and his father started working on a solution that involves plastic milk, adding some of that very carefully on the buttons increases the touch sensibility making easier for grandma to press them.
The little boy surprised his grandmother at Christmas with this simple trick!
Check the full post on instructables and make it yourself:
This solution shall not include mention to the use of drugs, chemicals or biologicals (including food); invasive devices; offensive, commercial or inherently dangerous content. This solution was not medically validated. Proceed with caution! If you have any doubts, please consult with a health professional.