Always try to invite them first. You have to know your own limits and what you can and cannot live with. Having someone non compliant and non functional in your home is highly stressful. It is often a gamble if taking such a step would assist them in “waking up” and getting help or if they would just choose the lifestyle they are living in and go further down the scale. An intervention should always be done with professionals who will guide you with options. Making sure they have a place to go is important, even it if is a shelter. But giving the option of getting help and continuing to live there or going to Salvation Army or somewhere similar gives them some choice and gives you peace of mind. This is a very hard and difficult situation. You want to have is planned out well with guidance.