The manager can only facilitate the decisions of the board, that is why they have indemnification clauses in their contracts.
I have refused to take on properties and terminated properties that neglected their infrastructure for this reason.
It is the same as a roofer telling a homeowner to fix the sagging roof or it will fall in. The roofer can’t proceed with the repairs if the owner does not authorize it. They are not liable when it caves in.
You can’t keep collecting management fees when you know there’s a structural problem. Period.