What exactly would a lawyer need to posses in order to prove the victim had a medical condition?

What exactly would a lawyer need to possess in order to prove, and have the right to show the jury that the victim had a medical condition, like post dramatic stress disorder?

And what would a lawyer need to prove that their client had lived on a certain lot longer than another neighbor?

A doctor and some mail or postal history.

He would need to possess a medical professional that could testify to that. Usually lawyers, in the course of preparing for a case, will decide what kind of, if any, professionals they need to testify to specific criteria. For example, in a a gun case, the lawyer may need to track down a ballistics expert to testify that a bullet could have or could not have behaved a certain way during the act of the crime in question. In your case, the lawyer needs to find a specialist (doctor) who deals in the specific area dealling with whatever it is that you need the doctor to testify TO. Get it?

The first part needs 2 things, medical records showing a doctors opinion on the diagnosis, and of course the doctor's opinion. You should be able to get that in discovery, but the patient may need to waive the doctor/patient privileged.

The second part just needs a quick search of county records, when real estate is bought the deed is transferred and recorded at the county clerk's office as a matter of public record. So all you'd need there is a copy of the recorded deed showing when the property was last bought.

You would need to get the person's medical records and maybe testimony from their doctor. By the way, it's post TRAUMATIC stress disorder :o)

For the second one, you would need the title deeds if they owned the properties, or the lease agreements.

documents and/or witnesses attesting to those facts, and relevance to the case at hand to introduce them.

If either are renters utility records maybe needed as they would not own the property.