What do I do?

Papa3773, have Mom-in-law tested for an Urinary Tract Infection. Such an infection in someone her age can cause all types of symptoms such as becoming violent, etc. If her UTI test is positive, it can be treated with antibiotics.

I never heard of Panadol, so googled. It sounds like the equivalent of aspirin, Tylenol, a med for mild pain.

Mom needs to see a doctor for diagnosis.

Your mother in law needs medical attention.

Call her doctor, or take her to the ER or an urgent treatment unit, and tell them what you've told us. They will investigate possible causes and give her appropriate treatment.