Research on glioma brain tumors shows the average latency period is 20-30 years.  Although cell phones were introduced in 1983, it was not until 2003 that over 50% of the US population had a wireless subscription, so the 20 year mark for mass cell phone use has not yet been reached.   The May 17, 2010 INTERPHONE study, the largest study ever to examine possible links between cell phones and brain tumors, concluded that overall there was "no increase in risk" for glioma or meningioma brain tumors,  but the average user in the study had less than eight years of cell phone exposure.  In his review of the INTERPHONE study results, Dr. Rodolfo Saracci stated that "none of today’s established carcinogens, including tobacco, could have been firmly identified as increasing risk in the first 10 years or so since first exposure." 
You can actually get a completely mechanical timer on Amazon for super cheap. Then all you have to do is plug your router into it, and set a time period, say from midnight to 7 am, and it will automatically turn your router off and then back on again. Depending on your sensitivity to EMF radiation, you could quickly notice better and more restful sleep.
Exposure to ionizing radiation, such as from x-rays, is known to increase the risk of cancer. However, although many studies have examined the potential health effects of non-ionizing radiation from radar, microwave ovens, cell phones, and other sources, there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans (2).
There has been no rise in the rate of brain cancers despite a massive increase in the use of cell phones. If cell phones were causing cancer we could expect a significant rise in the rate of brain and other related cancers. According to the National Cancer Institute, there was no increase in the incidence of brain or other nervous system cancers between the years 1987 and 2005 despite the fact that cell phone use dramatically increased during those same years.  Between 2004 and 2010 there was still no significant change in the incidence rate of brain tumors. Between 2004 and 2010 there was a slight increase from 209 cases to 221.8 cases per 100,000 people, but this slight increase was attributed to better tracking and recording of cases.  During the same time period, cell phone use increased 62.7% from 182,140,362 subscribers in 2004 to 296,285,629 in 2010. 
Legally there is nothing you can do to oblige your neighbors to remove their WiFi so you need to have a softly softly approach. Go and see them, have a friendly chat. Ideally take an RF meter with you, show them the radiation levels they are exposing both you and themselves to. Take some print outs of some of the studies that have been done on the dangers of radio frequency radiation.
Carlo’s October 7, 1999, letters to wireless-industry CEOs are the smoking-gun equivalent of the November 12, 1982, memo that M.B. Glaser, Exxon’s manager of environmental-affairs programs, sent to company executives explaining that burning oil, gas, and coal could raise global temperatures by a destabilizing 3 degrees Celsius by 2100. For the tobacco industry, Carlo’s letters are akin to the 1969 proposal that a Brown & Williamson executive wrote for countering anti-tobacco advocates. “Doubt is our product,” the memo declared. “It is also the means of establishing a controversy…at the public level.”18
In September 2014, Californian oncologists reported four similar case histories of young women who had developed breast cancer in precisely the areas where they normally carried their smartphones. What shocked the doctors was that these women were aged 21 to 39 and had no family history or other risk factors relating to cancer. All their cancers “had striking similarity, all tumours were hormone positive… (with) an extensive intraductal component and… near-identical morphology.” (CaseRepMed., 2013).