Yes it is true that high levels of BUN (Kidney failure) can contribute to headaches
and the two are related as if your uncle in on dialysis it will increase the headache.
The best temporary relief is :
Regular physical exercises. Proper physical exercises can promote metabolism
and revitalization so as to promote blood circulation. Exercises can also help relieve stress and nervousness
which are also factors causing headache.
Massage and acupuncture
. Rubbing or stimulating certain acupuncture points can help alleviate headache.
Medicated bath. Medicated bath has a lot of benefits to the body---alleviating fatigue, improving sleep quality, relieving stressful feeling and headache.