I own a small business, i have beautiful female co-worker, I asked her out she told me she had a boyfriend I told her I understand.
The atmosphere is not awkward since I treat her the same as before as if nothing ever happened and we work in the same room.
Even if she offered me sex now I would refuse since there is no point in drama or cheating, just to fulfil my ego and selfish needs.
Seems like your friend has 0 other options and lacks game skill to be able to attract any girl, and so he tries to manipulate his way to pussy.
Typical boy behaviour with a lot of fear.