I like Bettercallpaul's comment: "We all need wisdom..."
We could all use a little bit more of wisdom, which is basically how we understand and use the knowledge we have in daily life. I can have enough knowledge of how to be a millionaire, but if I waste money on everything, I am not using my money and knowledge wisely. Likewise, depending on the level of help your sister needs there could be more than one way of help: such as sending her money, buying of items she needs then bringing them to her, etc...But ultimately you will have peace about it all. Let me tell you a life example: God be the Glory!
My whole life I wanted to be a police officer, this year, I went and tested for three different police agencies. Two of them I was the person selected for the hiring process, but in my Spirit there was no comfort or peace over accepting it. I would pray, yet there was no peace, it is something I couldn't go through with because His spirit was not bearing with my spirit. When it is God's will there will be peace about it. I also have two years in college for a nursing degree, I had quit due to complications with something. But after I said no to the police, I prayed to God told Him my plan in being a nurse, and I have never been more sure of something because I have total peace about it.
Brother, what is God telling you? Read His word, ask Him to show you. Do you feel over and over again this is something you should do? Is there any peace? Do you find characteristics of God in doing it, such as joy, love, peace, comfort? Or do you feel uneasy, no comfort in doing so? It may be He wants you to but at the right time, in which you're right: waiting for God to open the door. When He does, walk through with boldness. Amen!