I had situations with family that are a variation on the same theme.The only way that you can make them care for a better hygiene, is to convince them. If you can not, than nothing what you will try, will help. My experience is that you have only a one to ten change to succeed. I am sorry for that.The second thing that is possible and that is what I had to do already more than once, is stop the contact with those people.Remember, there is a reason why they have nothing and de cause is more often to find in there way of living and thinking, than in an extern cause.