1 John 5:16 > If anyone sees his brother sinning a sin which does not lead to death, he will ask, and He will give him life for those who commit sin not leading to death. There is sin leading to death. I do not say that he should pray about that.
This does not mean (as many Christians believe) that we CANNOT pray for a Christian committing the sin leading to death. The passage clearly tells us it is right to pray for a Christian sinning, not leading to death. But gives us a choice if they are sinning, leading to death. If I tell you "your computer needs more RAM, but I do not say you should get a bigger hard drive" I am not telling you that you shouldn't get a bigger hard drive. I'm telling you that you do not need to, but if you want to, you can.