Seeking expert counseling is a sign of strength. A personal relationship with a caring professional is proven clinically effective.
You are at a crossroad where there is only one sensible and correct path to take. You are very kind and caring - not only about your brother, but about your employees. You are the leader and must be the strongest.
You say that you can get a loan on condition that he not be involved. That is a cold hard fact, not your value judgement. It is the business judgement of the bank or lender and that is not disputable. It may also be your judgement as well, and it probably is a good one, since he is not suited to be the one in charge.
Lay down the facts. Be tough minded and don't take any argument from him. You have no reason to be afraid of him. You are saving HIM and he needs to appreciate it and go along with the program, unless he wants out. That has to be the law as you give it to him. Perhaps you are not used to taking such a strong stand, but, to use an old cliche,
"when the going gets tough, the tough get going".
You are also under a great deal of stress
and this is causing you terrible anxiety
and perhaps a bit of depression. This is situational and is classified as Adjustment Disorder rather than as Anxiety or Depression. Fix the situation and the symptoms go away.
If you have a physician that trusts you then tell him that you want something for anxiety. Do not accept an antidepressant (such as SSRIs like Prozac, Zoloft, or Paxil). You want something that will get rid of your anxiety right away, that you can take as needed. What will help you is a benzodiazepine such as alprazolam (Xanax), clonazepam (Klonopin), or lorazepam (Ativan) taken only as needed in a small dose (for example, one half of the smallest dosage of any of those pills). I would recommend 0.25 mg (half pill) of alprazolam, only AS NEEDED. This can help get you through this situation.
Suicide is not your style and will hurt everyone. You wan't to help everyone so you must act tough and see this through. Hopefully your doctor will be smart enough to understand that you are not a drug seeker, and that this is exactly what you need to help you get through this crisis. When you solve it, the anxiety will stop.
Please watch over your precious self. Many people care deeply about you, even strangers like me.
Elliott Sewell, LPCC, NCC, CCMHC