No one can fully empathise with anyone else.
No matter how similar the situation everyone experiences it differently.
Few things annoy me more than someone saying 'I know just how you feel - the same thing happened to me'.
Sometimes people who have had a similar experience can be empathic and be with you in your pain. Others who have gone through a similar experience will say they understand and proceed to make it all about them.
EG on this forum the number of people that say 'Oh the same thing happened to me; this will happen next; you must do ... .' 'Oh you haven't done ... , how stupid are you, you are fooling yourself, etc etc.' Not much empathy there.
An empathic person isn't interested in whether they have had a similar experience. They accept that they can only imagine how you feel and they are there for you to tell them, they don't tell you what you should do, they don't criticise what you do do. They are just there for you. If they feel you are hurting yourself with what you are doing/believing they may ask questions to help you think through; they may offer suggestions, whilst totally accepting your right to not do it 'their' way.
I believe that someone who has gone through something similar and is also empathic can show the most understanding but an empathic person who hasn't can be more understanding than someone who has but believes that their own reaction is the only valid one.