Advice Needed with Accessing Medical Care for My 19 Year Old son

This morning for the first time in his life my 19-year-old son had a seizure. We called the ambulance and the paramedics were fantastic. They wanted to take my son to the hospital to get him checked out and to get blood tests done. But the problem is my son will not go to a hospital or doctor. In the end, they suggested just monitoring him; hopefully, the GP will speak to us tomorrow.

Now, my son has global development delay as well as autism. Everything about him must be checked out and we can't get him to comply. I have a lot of chronic health problems and he does have a good social worker.

Now, I know that the only way to get him checked out is to sedate him and I am going to discuss this with the doctor. The paramedics said this is exactly what the hospital would do. But he has to get there first. 

He does need blood tests. So, to me, sedation is the only way.  

I was also thinking about seeing if I could consult private medical care if the NHS doesn't work out.

Can anyone suggest anything?

His dad and I are at a wit's end. 

Thanks, Jayne x