Hi,
The employee is eligible for treatment. As you are asking now, probably he met with the accident in April or March. As you said he worked until the previous month, then that should be February. He is eligible for treatment until December 2016, provided he contributed to ESI for at least 68 days during October 2015 to February 2016. The reimbursement part may be difficult, but for treatment, I am sure that he can avail.
Thank you.