This looks good to me. For ease of flow, you could add some commas or dashes, I have a suggested some slight improvements but your original looks okay:
"Edward can use a few basic phrases. He has been able to introduce himself and he can also answer questions about personal details such as where he lives and where he works - but he is not fluent. It's hard for him to interact since his use of grammar structures is extremely limited. He only used simple present structures during the interview, and his vocabulary is also very limited.
He has been able to understand around 50% of the listened words, but this proves insufficient for satisfactory interaction.
He needs to improve his knowledge of grammar as well as his speaking and listening skills."