Yes, Seattle has a number of options for Seniors including a variety of Senior Housing Assistance Group (SHAG) apartment buildings which offer affordable rents to qualified Seniors.
There are also retirement condo facilities in most Seattle neighborhoods, where 55 or 60 is the minimum age. Some offer a range of independent to assisted-living care options.
In nearby cities surrounding Seattle there are planned ' village ' style communities with individual attached-homes, golf courses, and on-site community centers. It all depends on your lifestyle and your income.