Hi My Mother In Law Is Being Sick After Meals.

Hi my mother in law is being sick after meals. ?? she is 84 and I care for her. If I cook what she wants she is fine. At first she said her hip was bad then as she fond out her 2 friends had cancer she has it. took her to doctors and he had ex-rays done but fond no problems now she is dieing from her bad heart.?? what should I do for the best.??