Hi YNA, welcome to the Forum and I am so sorry to hear of your predicament. Like the others have said, this guy doesn't write English properly so there is every likelihood that he isn't a Brit and may well be attempting to scam you.
If you are still worried, feel unsure and can't wash your hands of him, for your own peace of mind the very best that you could be expected to do is to report his predicament to the British Consular Office in Kuala Lumpur. If he is a British National in distress and he really has been detained, I believe that the British Embassy would have been notified by the authorities and therefore they will have a record of him.
I have been in touch with the Consular office myself this year and they are very helpful. Contact details are as follows:-
Kelvin Joseph |Consular Officer | British High Commission, 185 Jalan Ampang, 50450 Kuala Lumpur, Malaysia * email: Kelvin.Joseph@fco.gov.uk ( telephone: +603 2170 2345 | fax: +603 21702390 |) ftn: 8402 2345 | website: http://ukinmalaysia.fco.gov.uk