Hi Tam,
I would say a loooot of people speak English pretty well in Portugal, it was or is (they were about to change it recently, so not sure anymore) mandatory in school. Older people (65 and over) don't usually speak it. Kids and teens should speak enough to communicate almost anything, the ones that don't probably hated the language, were slackers or just have learning issues. Middle aged adults know the language well if they had a decent education, the better the education the greater the knowledge.
Another thing that really helps is the fact that we use subtitles on t.v, this really helps us build our vocabulary, work our pronunciation and keep the 'rust' away hehe. I learned Italian in Uni, and the rust there has accumulated over time lol.
In my case I can say I am fluent in English, I might not recognize some expressions, or terms, but this isn't very common. I am an exception though as I have lived abroad and I have had an international education, even when residing in Portugal. I spoke English every day, so it is only natural that I am fluent.
As to my family, my siblings are all younger than me, from age 19 to 23 and all speak English, some better than others, even though they all had similar education. One is living in London at the moment, and is doing very well professionally. My mother speaks decent English, although one of my brothers mocks her, my stepdad speaks it a bit better, my father speaks it just as well as my stepdad. My grandparents never spoke it, none of them went beyond fourth or even second grade, as was usual in those days.