Edward Kennedy was the youngest and last of a great generation who many have compared to royalty in America.
After the death of all three of his elder brothers, (Joe during WWII, and John and Robert by assassination) Ted Kennedy was expected to run for president. But when he did, his attempt was blighted not only by the notorious Chappaquiddick incident but apparently by not really being committed to the goal.
Despite this, Kennedy became famous for his political work in the Senate, becoming a byword for liberal views and speeches, earning him the nickname Lion of the Senate. In some cases his views were extremely unpopular, only for them to become accepted as years went by.
He was a sufficiently iconic figure that someone might reasonably collect items relating to him exclusively. Certainly many would be very interested in collecting memorabilia relating to him alongside his brothers, even if they had little interest in collecting anything else.
There is of course a brisk trade in objects relating to Kennedy now that he has died. However, the things which will be of value in the future will be those which had significance before he died, such as those from his presidential campaign, original photographs of him and especially his signature.
Collectors may regret buying the Ted Kennedy stuffed dog (why not a lion?) on a whim.