Can a sin lead one to hell even under grace? (this is not a Catholic post regarding mortal and venial sin)

I have a belief that all sins mentioned in Galatians 5:19, 1 Corinthians 6:9, Revelations 22:15, and the sins referred to in "those who commit this sin shall not inherit eternal life" are sins which lead one out of grace. In my country, there are some people in vanity sin but who are clearly with the Holy Spirit. For example, my mom has cast out a demon from my grandpa although she is in vanity sin. But how could she cast out this demon without the Holy Spirit (salvation)? If someone is in a sin such as sexual immorality he/she seems to have NO authority against demons. This fact might show that such a person has lost the Holy Spirit because of a sexual sin. But why does someone in vanity sin seem to still have the Holy Spirit? Sometimes I fall in sexual sin and I clearly feel the Holy Spirit is getting away from me. Is there anything in literature regarding this problem?