A mentally ill person lacks the normal emotional/mental balance that most people have. Looking after a mentally ill person needs a lot of effort, time and patience.
To look after them, you need to know what exactly is the kind of illness the person is suffering from, what is the cause and what medication and measures can be taken to avoid the condition from aggravating. Get a thorough knowledge about these aspects from the psychiatrist treating the person and strictly follow the medication and therapy sessions they advice.
Apart from that you can take some measures to avoid upsetting or aggravating the condition of the person. For example, do not ever use words that sound derogatory or ridiculing.
Avoid using words like ‘crazy’, ‘weird’, ‘mad’, ‘insane’ etc to refer to the person. Even at times when you are angry or very frustrated stop yourself from making comments like ‘you are crazy, insane’ and so on. Do not make their condition very obvious and open to them.
Give them space to follow their ideas and thoughts, but do keep an eye on them. At the same time, be careful not to make them feel like they are being spied upon and being watched constantly.
Try to engage them in activities they like. It could be watching cartoons, reading stories, drawing, painting etc. Do not expose them to movies that have high content of violence or emotional drama.
Do not speak in a high tone or put on the radio or television at high volume. Keep the disturbance minimum especially when they are resting. A peaceful and calm atmosphere is essential for the well being of mentally affected persons.
Avoid displaying your sadness, frustration, helplessness or anger before them. Do not yell at them or punish them for errors or simple mistakes. Do not speak to them in a condescending tone.
Give them your love and understanding. They need to feel valued, wanted and loved.