Sounds like my now deceased eldest sister, 10 yrs o!der. I could count with fingers left over on my hands the number of times we talked on the phone (mostly when my family and i were caring for our terminally ill DAD. She didn't write letters or send cards. But for she was alive i knew i aways had a safety net; That i could show up with kids and critters in tow and be welcomed.
A couple of years later the 2nd oldest, 8 yrs my senior died. So have i have just one older sibling left, either 5 or 6 and a quarter yrs older-- always sensitive about her she may have fudged it by a year. (She's the one i've talked about who when we lived in same city wanted me to dye my greying hair cause 'everybody knows you are my younger sister'.)
We email and call. She always had some memory issues (for more than one reason) but it is getting worse.