No Muslim does not know that Prayers are obligatory on every Muslim unless he lives in the jungles where no one knows anything. You must perform your missed obligatory Prayers as Qadha.
If the ejaculation occurred without intending to do that, Qadha is must of that fast. Kaffara is obligatory if it was done intentionally. But how can one masturbate with out intending to do it? Was he sleeping. If he masturbates while he was awake then he has committed it intentionally. If he masturbated but his intention was not to reach to ejaculation, and ejaculation occurred with out his control, that might be possible.
OTP entered does not match. Please enter the correct OTP!
Full Name and Password are required.
Please provide a valid Email address.
Please enter a valid email address.
Enter valid first name and last name with at least one space.
Mail sent successfully!
A validation e-mail has been sent to your e-mail address. You will need to follow the instructions in that message in order to gain full access to the site.