If they are over 30 as the younger one, not so much. They've gotten past the independent stage. At the same time some mature a lot quicker, like other countries. I have a family member with quiet a bit age difference, but she went into it knowing she would end up being his caretaker and once he passes she is free to marry and start a whole new life.
But I see he always worries when they go to a restaurant that she might find someone better than him. She has to constantly reassure him. She works as a nursing assistant, so her work comes out in her everyday life of looking out for him. She doesn't have plans to stay on this country once he passes, as she misses her family.