How do I handle having more money than my sister?

My husband and I have come into a bit of money, which is a very good thing, of course. But my sister and her husband are struggling a lot. They made their choices in life (choosing to drink and smoke, spend unwisely and she hasn't held a job in years). They aren't asking for a handout. But now we are planning to build our dream house and it seems to be hard for my sister to be happy for me. I know she wants to be but she's under such stress financially. I feel bad for her but does that mean I shouldn't talk about all our plans? Should I not show her how excited I am about all this? I really want to share my joy with her but instead, she's sort of taking the joy away from me by being envious. How do I handle this?