Yes. Yes it is hard the withdrawal effects and need a supervised detox.
Yes. Daily use, implies inability to cut back, other criteria are the compulsion to use, disregard to consequences. The risk of daily use is also withdrawal, dependency etc. Recently daily use has been implicated in causing schizophrenia, and increasing testicular cancer.
Yes. It is better to get help there might be options you are not aware of that might benefit plus you would get counseling and be involved in a support group.
All depends. If they are abusing it, or using it recreationally, then yes. If they are using medication appropriately, under a doctor's supervision, no.
More than usage. Daily use is not as critical as the consequences of one's behavior when using a drug, be it alcohol, tobacco, licit or illicit drugs. Ask yourself these questions have you tried to cut down on use, has anyone been annoyed or criticised your use, do you fell bad/guilty about your use, have you used in morning as an eyeopener. A yes to any suggests a need for rehab/recovery.