If you accept him as is which is what unconditional love might mean, wouldn't partaking in a sick relationship with him be part of that because you would be loving him unconditionally?
No. That is where boundaries come in. Boundaries are loving and healthy. Two individuals in a relationship not one enmeshed cluster.
M22,H45,W45 S21/18D12 Retain faith that you will prevail in the end, regardless of the difficulties and at the same time confront the most brutal facts of your current reality, whatever they might be.