Is it normal for a cause of death to stay pending until toxicology comes back?

My 37-year-old brother passed away very unexpectedly. My sister in law woke up to him gasping for air. He was my only brother, my baby brother and I’m still trying to wrap my head around all of this.

We were told that his cause of death is pending on the death certificate until the toxicology results come back. I’m just wondering if that’s normal when someone young dies suddenly.

At the hospital, they mentioned things like a possible cardiac event or pulmonary embolism, but he didn’t have any major health problems.

The one thing we do know is that he had been vomiting a little blood, and what he described to my mother as looking like coffee grounds, and there was a possibility that he could have had a stomach ulcer.

I’m mostly just trying to understand the process
When they do toxicology after an unexpected death, what are they normally looking for?
Prescription medications, alcohol, drugs, medication levels, other substances? And is it pretty common for the medical examiner/coroner to wait for all of that before giving a final cause of death?

I think the hardest part right now is just not having an answer. He left behind 3 young kids😔Any insight from people who deal with this regularly would really mean a lot.

Side note- he’s already been cremated. Are we ever going to find the true cause of his death??