Parent wants sibling to visit. Help.

Do you know why she wants him to come? There doesn't have to be a reason, she just might want to see her son. If she really wants him and you think you can manage it, invite him for a specific time and activity, like for lunch from 12-1. He comes, you all eat, he leaves. Try to plan as much as possible, and it might not be so difficult. Address the usual triggers in advance. What does he threaten about and how can that be avoided? What does brother need? Can that be addressed preemptively? If he doesn't want to come, don't force the issue and try to be nice about it. His mother is dying, and he is likely to show up at some point. Is Dad also his father? Can he get a vote in this? Can he talk to brother about keeping it short and sweet for Mom, but not accusing him of being disruptive? Brother may be an A$$, but even they sometimes respond to consideration by being less of one.

In my opinion- tell him Mom would like him to visit. Then if he chooses to maybe a visit at lunch in public. If he chooses not to. Tell Mom you invited him, he declined. God bless

Is it at all possible to get mom out to a "neutral" location. A restaurant, a park some place public?
If that is possible there might be a good chance that he might better behave.
If that is not possible could you ask the Hospice Social Worker or Chaplain to be there to help the situation? Again brother might be on better behavior if there is a "neutral" party there. It might even be possible that mom could be moved to the In Patient Unit for "respite" so that brother again would be in a public space and less likely to cause problems.
All this might not be needed if your brother is facing the reality that mom is on Hospice and is in fact reaching the end of her life it might make him see things in a different light.

Get him to make a phone call- say he’s got flu so can’t be there in person fir her to catch it and have a call

Wisdomseeker: A zoom meeting may suffice.

If you can't do a Zoom meeting for whatever reason, have the visit take place in public, such as a park with lots of people around. You could also hire an off-duty police officer, male or female, to be present, or a security guard. You could put a time limit on the visit and have brother escorted out when time is over.

People do this in divorce issues when the soon-to-be ex is entering the home to collect belongings, etc. It might be worth the expense in your case.

Or you could just say no, you and dad are not having brother to visit, and that's that. It isn't as heartless as it may seem, considering that your mom deserves protection from anyone who would harm her by word or deed.

That is a good idea. Thank you.

Can you do a zoom meeting or something like that? That allows you to put an end to the visit when he starts showing signs of instability.