i had two within a period of 6 months around 4 years ago-i was 41 years old.
i had no history of high blood pressure, high cholesterol or the like. i did and do have a terrible time with migranes. both of mine were preceded by t.i.a'.s which are also known as 'mini strokes'-they can mimic all of the classic signs of a full blown stroke but the affects (for me drooping facial muscles, right side weakness, loss of verbal skills) disappear within about 24 hours.
the permanant effects of my strokes are hearing loss in my right ear, loss of peripheral vision in my right eye, and some issues with short term memory-and when i'm realy tired or stressed my right side will get weak/i get shaky and my speech gets aphasic (i know what i want to say but the words come out wrong, or i will misprounounce or slur words). initialy after the strokes my reading ability was shot-i could read but i found myself re-reading the same stuff over and over to get it to absorb or to remember it so the subsequent material made sense (i developed a heavy addiction to tabloids-short articles that helped me with both memory and reading speed. i can read normaly now but it's one addiction i've never kicked

).
depending on what contributing factors can be determined to have caused a stroke lifestyle changes can help prevent further ones. for me both were preceded by incredibly stressful events and numerous headaches and migranes so i have to be aware of what's going on in my life and try to steer clear of family stuff that i can't control/will cause undue stress. i have to make sure that any medical person i see is aware of my history and takes that into consideration when perscribing meds (i recently was given a perscription for a pretty run of the mill antibiotic and started getting bad headaches within a few days, found out one of the less common side effects was headaches-so i had to get an alternate drug). i have to know my physical limits and take that into consideration (i have nowhere near the energy levels i had before-if we are vacationing even if i feel great i make sure i get enough sleep). my doctors monitor me for the know contributors to strokes and while a slight increase in cholesterol or blood pressure might be deemed 'wait and see' for another patient-it's addressed immediatly with me (i might have to quick change my diet to total no salt/no bad fats/high good fats to get back within acceptable ranges).
having one stroke does'nt nesc. mean you will have another (i know a young man who had one out of the blue at age 16-his was caused by an issue that once corrected will likely never happen again)-but you need to be aware and make the people around you aware (my kids are 9 and almost 12 now-but they got clued in quick to let me or my husband know if they noticed i was favoring one side or 'talking funny'-sometimes i dont initialy realize i'm showing symptoms).
the realy great news is that with timely physical therapy alot can be regained/recovered. it's amazing what a good pt program can do to help regain strength and mobility.
good wishes to your family member-the issue with speech can be realy frustrating. so patience on both their part and the people around them is key (i wanted to communicate realy badly, and esp. with the kids we had to get them to stop talking for me-it was only through practice, trial and error that i could work on it).