I am so angry with my brother in law! Should I be? Is it my right?

Sounds like your brother in law always feels like he got a safety net or some one to cover for him. Understand he is your husbands brother, and brothers should look after each other. However you guys are now all adults, and you should not still look after him like he is a spoilt child. Set some boundries, maybe a limit or other means to get him help, both financially and emotionally , and maybe give or tell him where he can find more guidance in setting his life straights. You are doing the best you can, and your husband's brother's behaviour or way of living immaturely should not affect your standard of living and happiness.