The distribution of power in the US is top-down. As the head of state, he was responsible for either instituting or delegating the policy and procedures of dealing with the aids pandemic. This ranges from healthcare to public outreach. He hired his cabinet, he had tremendous power to sway and inform public sentiment. He was one of the most popular candidates in the history of the US. He won 49 states in his re-election. The ignorance and homophobia that exploded in this time could have been mitigated to a large degree.

You're correct on saying it was mishandled on many levels. Those levels were all largely subordinate to Reagan's cabinet. The director of the CDC is appointed by the president. He could've.influenced how aids was researched, treated, spread, and traced. The responsibility for the poor treatment of aids falls squarely on Reagan's shoulders