I work in financial planning, an industry dominated by grey haired people in suits. And I frequently get asked about how to get more young people in the industry. Here are some thoughts about changing the demographics of an organization.
Recognize the biases in your org and actively recruit people to your organization to correct those biases.
Their titles should be the same as others in the organization. For instance “financial advisor” not “nextgen financial advisor”
Recruit them to be in leadership positions and trust them.
Remember millennials are just regular adults at this point.