Mum needs some Advice

Puss' Mum here.  The BFGC has been a bit poorly, and I'd appreciate some advice.

The BFGC started coughing nearly 3 weeks ago.  It's a sneezy chesty cough, which sounds different from the sound you get when a cat is being sick, which is more stomachy - if you know what I mean.  He's never been a cat to cough up fur balls, which is surprising considering the amount of time he spends licking himself! This will come on for no apparent reason - one minute he will be asleep, and the next he will be coughing.  I have filmed him doing it (that really made me feel bad!) mainly so I had something to show the Vet.

So, of course, we took him to the Vet.  The first time (without the video), the Boy-Vet had a good prod and poke, but said he was inclined to leave things to see if it settled by itself.  It didn't, so a week or so later we went back.

This time we took the video and showed it to the Lady-Vet.  She said his chest, etc, sounded clear, but managed to get him to cough whilst he was there when she was feeling his neck.   She thought that he might have a bit of grass or something similar stuck behind his soft palate - this is quite common, apparently.

So, the following day, he went back to the Vets and was sedated.  They had a good look at his throat and up his nose, and took x-rays of his chest.  Everything looks fine - the x-rays were clear, apart from the fact they thought there was a bit more mucus in his nasal passages than they would have expected, although this wasn't discoloured in any way.

The BFGC has come home with some antibiotics, although the only way we can get him to take them is by crushing them into powder and coating prawns with it. He has been taking these since Wednesday, but is still coughing and there doesn't seem to have been any real improvement as yet, although maybe it is still a bit early.

He has to go back again on Tuesday, but obviously we're worried about him, and the coughing is quite distressing. In himself, he seems fine.  He's eating normally, the business end at the back is fine, and he's doing all the things he would do normally.  He sleeps a lot but no more than he usually does.  He hasn't lost any weight at all.

The Vet mentioned heart worm, but we don't think that's it.  There isn't heart worm in the UK due to the weather, and although he has been abroad, that was nearly 3 years ago and we feel sure we would have seen some other symptoms before now.

Our current feeling is maybe asthma, but we would appreciate some advice from the Kitty Blogosphere.   Video follows:

Thanks muchly in advance.

BFGC's Mum (and Dad!)