A great Christmas gift idea for your grandson who is into self-improvement would be a book or a course on personal development or self-help. Some bestsellers in this category that might interest him are "Atomic Habits" by James Clear, "Mindset" by Carol Dweck, "The 7 Habits of Highly Effective People" by Stephen Covey, and "The Power of Now" by Eckhart Tolle. Alternatively, you could gift him a journal or planner to help him organize his goals and track his progress. Another possibility is a meditation app subscription or a mindfulness course to help him practice mindfulness and reduce stress.
Or you can get him a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.