If you have retained the right of residence:
If you have the right of residence formerly in the UK, then you can apply for the EU settlement family permit as someone from the EU, Switzerland, Norway, Iceland, and Liechtenstein family member. You are staying with a British national in the EU, Switzerland, Norway, Iceland, or Liechtenstein. This is called “retained the right of residence”.
You are eligible to have this permit if you are their child, you are in the process of education in the UK, and they died or left the UK. They had a child with them, they are died or left the UK, and the child is in education in the UK. You must have an approved British Passport and evidence of the relationship like a marriage certificate, Birth certificate, and civil partner certificate, proof that you are constantly staying in the UK.
If your family member is not alive then proof of death is attached as a death certificate and cause of death, employment certificate if job holder. Your application will be online and filed while you are from outside the UK.