If you live in a region affected by the war in Syria then you have been dealing with the issue for several years now.
If not then this is no different from Libya, Djibouti, Yemen, Afghanistan, Iraq, Kuwait, Yugoslavia, Somalia, Philippines, Panama, Colombia, El Salvador, Lebanon, Grenada, Vietnam, Korea..........need I go on?
Read the list of nations we are in now with boots on the ground:
http://en.wikipedia.org/wiki/United_States_military_deployments
[Spoiler: it is 150]
If you really want to learn how often we have put men on foreign soil to actually fight then try reading this list:
http://en.wikipedia.org/wiki/Timeline_of_United_States_military_operations
Basically, we spend far more time in foreign war than we spend at peace with the world. That second link has literally
hundreds of belligerent foreign deployments by the US. The longest stretch we ever went leaving the rest of the world alone was our Civil War. Name just about any country and it is very likely we went there putting our rifles in someone's face at some point in the last 238 years.
While it should bother you about the vast scope and regularity of our "interventions", you simply cannot let the anxiety of any of them individually get to you because you will never get any sleep.
Getting back to your windfall, your best bet is dealing with any debt first. Yes, I know that sounds dull and boring but in the end paying down any debt will return that spent money eventually in saved debt interest costs.
Next important issue is an emergency fund. Even fixed income folks can run into payment stoppages or unexpected expenses. You should always have several months worth of living income saved at all times.
If you happen to be debt free and have an emergency fund then look to the fundamentals first. Water, food, security, and shelter. If you don't have a high quality water filtration system then look there first. Sawyer and Katadyn both make filters approved by many here.