How do you help a family member that is mentally ill?

Clearly these symptoms are characteristic of schizophrenia or similar diagnosis. Schizophrenia in particular, usually kicks in around early adulthood, sometimes later.
Mental illness can be so hard to treat for many reasons. There are a number of organizations available for assistance, like your local NAMI (national alliance on mental illness- http://www.nami.org/).
Family members need to be united to do what it takes to get the loved one help.
If he becomes a threat to himself or others, he can be involuntarily committed to a psychiatric hospital for a few days, and they will be able to diagnose and treat him at that time.
Schizophrenia is particularly difficult because those who suffer from it often can’t accept that they have it, and become non compliant with medications.
If you end up approaching him and he’s willing to see a doctor, I recommend you go to a clinic in the nearest major city, that specializes in schizophrenia…trust me, don’t fart around with the local psychiatrist in some podunk town.
I got my brother (who has bipolar disorder) to go to the clinic in Philly (1.5 hours away) and he’s been stabilized for a year.
Good luck.

I have an uncle who has schizophrenia and i know it might be upsetting for you to see your brother like this but just keep calm and treat him like you always have done in the past. don’t undermined him or treat him like a child he will know,people who have this illness are very clever. It is best to agree with him when he has outbursts and try not to say anything that will make him more paranoid, also try to have one person he trusts and can relate to as overcrowding can make him more agitated.

You have three wonderful answers here already, and I hope you will take them to heart. I would like to add that you can show your brother total acceptance and unconditional support no matter what. Sometimes that has to take the form of insisting he get help he doesn’t think he needs, but that is love in action.

Then be sure to educate yourselves, and particularly his wife and children, if any, about his condition, and give them the support they will need. Find a support group if that will help.

NAMI is great for this — free education, lots of resources, helping to break down the social stigma, and more. Support groups, etc.

The best place to get information quickly and without cost is your local NAMI affiliate. Don’t hesitate – call them.

My son has had schizophrenia for 10 years, and here is what I have learned. First figure out if you have any power over the situation. For example, you cannot relieve his symptoms, for force him to see a doctor. However, you can leverage what influence you do have. If my son doesn’t go to his doctor, I hold his spending money until he gets there. If he doesn’t take his meds, I go to his home an sit there until he does. (He will do anything to get me to leave.) You must always be there to pick up the pieces when the psychotic breaks occur. Remember not to get angry, because it is the disease not the person causing the problems.