Are you trying to encourage his independence though, really?
From this post, you clearly felt it was perfectly safe for him to get the bus, as that what what you encouraged him to do and hoped he would as a way of gaining confidence.
He then changed his mind and stared crying-it was his choice, not because you were frightened of knife crime because you wanted to encourage him to get the bus.
His choice should have been-get the bus (the bus you were happy for him to get) or don't go.
After a few more choices like this, where he prefers to stay at home crying, he would find that his choice was to be a weeping Billy No Mates or get on the bus.
You tried to bring in another option-that your DP stop whatever he was doing-even if that was counting the freckles on the end of his knob-and drop him at his destination.
That is pandering. It wasn't 3 am- take the bus or stay crying. By offering him a 'get out' the of course he will do whatever is most convenient for him.
The next time, it's the bus or stay at home. After a few times of realising that he will not be ferried about in broad daylight to social events, you will find-I almost guarantee it- that he will start to realise that he can indeed cope with a bus journey.
A bus journey his mum was happy for him to take until he thought crying would lead to a lift. And he was right, wasn't he, if his dad hadn't said no-good on your dad.
Now, from your feisty replies you are hanging around the house with a face like a slapped arse because your son couldn't manipulate his dad.
Poor guy- two kids crying to get their own way-it is nothing more complicated than that and you supporting them.
Get off your arse, take the two criers out for a two mile walk, buy ice-creams and get the bus back. leave your DP in peace and it will do you all the power of good.
Take plenty of tissues!