Board chair wants out

I’m the only full time employee and the executive director of a foundation with a budget of just under 1 million. I’ve been with the org for about 2 and a half years ago now, and I learned pretty quickly that the chairman has been kind of checked out for awhile now. His term doesnt end until the end of 2027 but he found his out because he’s agreed to take on the role of president of our endowment (current president is retiring) and he’s tasked me with finding his replacement for chairman. The issue is, there isn’t really anyone currently on the board that could take on the position of chairman besides one person and she has expressed before that she just doesn’t have the time to make that kind of commitment. We have a few board members who are great but they just don’t have the connections and the pull that the current chairman has and some can’t do it because of conflict of interest (we help nursing students and provide grants to their schools).

I don’t what to do at this point and I feel like it shouldn’t all be falling on me to find his replacement. He’s known for awhile that he’s wanted out but hasn’t made an effort to find someone who could fill his role. What would you do in my situation? This issue alone is a big reason as to why the previous executive director left.