Are my sentences strong enough? (Do I have to change or add anything?)

Answer:
I would change "Martin's and his family" to "Martin and his family's" and "his family" doesn't need to be in parentheses.
I would change the first commentary sectence to "Martin's Grandfather speaks in sioux which is his native language." and go into futher explanation on what he "knows". It's kind of a cliff hanger.
For the second commentary sentence, you should make sure to mention who's grandfather you're talking about if they are multiple in the story. Also I would change the sentence to "The grandfather exhibits his culture while wearing traditional clothing. The traditional clothing is typically worn by people of his tribe."
For the last commentary sentence, I would change it to "The quote states that the males in the family still follow traditions because it will eventually be passed down through generations.
Explanation: