Thank you for asking. Although, it is difficult to say without examining the patient, but the above mentioned symptoms are suggestive of irrelevant, suspicious behavior. Non sensible talks, suspicious towards strangers, talking to self, unpredictable behavior, etc are indicative of a psychotic disorder. If it is being present since years, a possible case Jd Schizophrenia can be suspected. The person with such problem usually is very suspicious, hostile, unsocial, guarded. At times there is also over involvement in religious matters etc. It needs to be treated with medications. The biggest obstacle in the treatment is that they are not willing to comply to medications because there no insight into illness. They deny that there is something  wrong with them.