If you know someone that has an addiction, then it can be very difficult to watch them suffering with it. You want to reach out and help them. It can be very difficult to help them if they cannot accept that they have a problem though. They may get angry with you and not want you to be around them or think that you are interfering and so it may be better to keep quiet.
It can be difficult approaching them as they may not be prepared to listen to you. It can also be difficult to know exactly what to say as it is a sensitive subject and you do not want to upset them or cause problems with the relationship that you have. The best thing could be to wait for them to come to you for help and be there to support them when they need it. One thing that you must not do is to help them financially as it will just give them the means to carry on. It can be very difficult watching someone struggle financially as well as emotionally.
You could try getting in touch with a professional to help them, but this may not work. While they do not accept they have a problem they may reject this help. Once they do accept it then you can help a lot. Gather some resources for them, so when they do ask for help you can provide them with it. Find out about professionals who can help them and offer to make them appointments and go with them, if they wish. Be prepared to help, but no offended if they turn you down as it may be something that they want to tackle on their own. Just be ready for them if they need you.