He said to buy a pair for grandma, but you lost grandma's pair: is grandma still there? This is grandpa's charge. Tell your grandmother that she is very old and take good care of other relatives for her. You lost it, probably because grandma is still here.
You burned a pair of shoes for grandpa. Yes, the dream has come true. Because of your filial piety, he will receive it, and his new journey will be more comfortable, so don't worry. Good luck!