I’m not certain what you mean by the term “safe.” Do you mean safe in terms of it being a physical risk for you to be involved with an individual who is experiencing voices and premonitions? Or do you mean safe in terms of his psychological health with regard to being in a relationship?
Generally speaking, individuals who are psychotic have a slightly increased risk of violence. Individuals who have a well-controlled psychotic disorder (i.e. consistently adhering to treatment recommendations) are generally no more dangerous than someone without a psychotic disorder.
An individual who is experiencing psychosis and who is not on his or her medication has an increased risk of violence. The best predictor of future violence is past violence. It would be advantageous for you to determine if he has a history of violence. If so, your safety may be at risk.
When someone is psychotic, they are psychologically unstable. Psychosis requires treatment. It generally does not improve on its own. If and when he begins taking medication, he would likely become more stable and consequently more capable of being in a healthy relationship.
I can’t say with certainty whether you should begin a relationship with this individual but you must be cautious. An individual who is experiencing psychosis and who is not adhering to his or her recommended treatment will be psychologically unstable. In that case, it would be inadvisable to begin a relationship with an individual who is psychologically unstable.
If this is a relationship that you plan to pursue, you should consider becoming educated about psychosis and psychotic disorders. Please take care.