My mom says she can’t utilize tax write offs on her real estate?

[Greyden Piechnick]

Hello!
My mom owns 5 rental properties. She is telling, me since her and my stepdad make over $150,000, she cannot utilize tax write offs until they sell the property. She is claiming that the write offs will  be used to offset the capitol gains tax when they sell. 
Is there a way for her to utilize the tax advantages of real-estate through the 30 year ownership?
What happens if she never wants to sell and pass it down to kids? 

How can the tax advantages still be used? 

Surely there has to be a way, as Brandon and David use the advantages and they make way more money! 
pls help. Thank you!