Actually, apple varieties are preserved via grafting. If you take an apple seed, the tree that will grow from it only has 50% of the DNA of the tree that made the apple. So there is absolutely no guarantee that the taste was preserved across generations.
Apple grafting is incredibly easy and cheap. All you need is a bit of knowledge, a utility knife, cheap flagging tape and ordinary waterproof wood glue. Planning to procure scions and watching for the bark slip is necessary - usually right around when buds start to break. My first graft was successful. Now I graft all the time. Peaches were a problem for me until I learned that they must be grafted after blossoms drop - usually later than ideal apple grafting time.
Specifically grafting is most likely in his case. You could go real wild and have a single apple tree producing all kinds of apples while being self pollinating.
I got one!, there are only 3 trees in existence (only 1 mature enough to fruit and 2 cuttings) rn and the apples taste kinda like pears but with an apple texture.