Sometimes a person can be unaware that they are no longer in their body and can be earth bound. This doesn't mean that all earth bound spirits (or ghosts) are unaware of their death. Some chose to stay on Earth for a myriad of reasons (ie they are not ready to go or have unfinished business).
But sometimes when a death is fast, traumatic, or their is confusion in the body; a soul can stay on the Earth plane and carry on with their usual daily or weekly routine.
This confusion can happen in a:
1. Sudden/unexpected/or traumatic death - Whether it's from natural causes, an accident, or self inflicted; a soul that is unaware that their spirit left their body may carry on with their daily activities or be left in the physical state or place of their death.
2. The soul's spiritual team is not their to help it cross over - This is a rare occurrence. 99.99% of the time someone from the soul group is with the person as they cross over. People who are passing often say they see someone (that is currently deceased) as they are crossing over. But again in very rare cases, there can be no soul there. Intuitively, I get this happens when the death was untimely. I hesitate mentioning this instance because for the most part their are several planned scenarios for a soul to crossover which are known by the 'team', but with anything there are always loopholes. If this happens and a soul is alone, the person can ask for their guardian angel or a helpful spirit from the light to appear and help them. They will instanteously appear once that petition is said.
3.When someone is under the influence - Drugs and alcohol cause a number of unfavorable influences. Besides not having your physical facilities, a person's spirit can be compromised too. Entities be it positive or negative are attracted to people who's souls are not fully present in their bodies. Some of these spirits can inhabit a person's body or at the minimum influence a person to do things (ie soul blending) they may not usually do. The liquid courage is real. Unfortunately, if someone dies while under the influence they can be stuck in an endless loop confused of their whereabouts. Or stuck in the location of their death or confused why their loved ones cannot see them (Spoiler warning ie Bruce Willis in the Sixth Sense)
Chances are as an intuitive you may have picked up on the restlessness of a loved one. You can intuit when someone didn't cross over either through a natural sense of knowing, any other "clair" sense (clear hearing or clear seeing), or through a communication dream.
If you want to help a soul cross over:
1. Delicately and slowly tell the soul what happened as they crossed over (replay the events of the day as best you can), tell them they are now deceased, and they can go to the light. Ask someone from their soul group to come forth and assist them to the other side.
2. Bless the area of the person's death - As their spirit can still be lingering at the site of death, especially in the case of murder or accidental death.
3. Go to a medium - Mediums communicate with interdimensional beings, not all psychics are mediums but mediums can be psychic. A trusted medium can be your go between to bring a spirit home.
Personally I would lean on working with a professional. Don't do this alone and engage with a friendly spirit you know or else you are bound to have a learning experience.