Leukemia is a healing phase so called cancer. Your father-in-law is likely recovering from a severe devaluation conflict. These types of conflicts usually occur within the family itself.
Chemo kills some people before the disease does. Chemo is highly profitable and I suspect that the producers are no better than drug pushers in the slums, just cleaner cut and drive nicer cars.
The chemo likely slowed down the healing process which in some ways is good, but there are safer routes to take.
Palliative measures are all good. But the most important thing of all is DO NOT PANIC. Its the panic, shock and fear that makes things much worse or even can trigger metastasis.
Another thing to be on watch for is any edema or swelling within the brain. These swelling can be seen on CT scans, but most physicians are not trained to recognize them. The use of ice for any head pain is good along with any natural diuretics such as dandelion root.
In the past childhood leukemia was often not treated and left to mend on its own. The child patient will be ill for several months and usually recovered.