Depending on state, they likely play 50% or more in total taxes, and are happy with it.
They are in Florida, no state income tax. About $3600 a month comes to him for disability. Based on possible agent orange exposure in Viet Nam. That is (I believe) non taxable. He also gets ALL his property taxes erased because of that. They both get SS on which there is no SS tax and 20% of it is exempt from income tax. Each has a pension, on which there also is no SS tax.
So I don’t think their tax burden is too onerous for their income level.