Very good questions all of us should ask ourselves when we're younger. They say the only thing constant in this life is change. We can consider ourselves fortunate if the good relationships we have now with friends and family are still there in the future.
Who knows what the future will bring, but you're ahead of many of your peers by thinking about how you might be in 30-50 years. Having long term perspective is the best one to have.
Good luck!
RE: Dear future Me: a letter for my self in 50 years