I lived with a boyfriend for 6 years who had grand mal seizures on a regular basis. As far as I know, the advice here is correct - nothing in the mouth, don't try to restrain or move them, head to the side is best if possible.
The one thing I would do is catch him as he went down whenever I could and lower him to the floor gently, to try and lessen the blow to his body parts striking anything around. Also I would put my hand under his head so he wouldn't hit it on the floor, although at times I feared that could have resulted in broken fingers or something.
He would always make that snoring sound towards the end of the seizure. When he woke up he would be extremely disoriented, and I'd have to tell him over and over again where he was (he was also blind). He's hear a car go by and ask what street we were on, and then when the next car went by he'd ask again. The lesson there of course is don't leave someone alone to take care of themself afterwards, even after they wake up.
He never needed emergency care, just rest afterward - he'd usually go to bed for the rest of the day with a headache.
A couple of months after I left him and moved out, he had a seizure one day while making coffee and ended up in the hospital with serious burns on his hand and arm. It was pretty hard not to feel guilty about that, even though I knew the same thing would have likely happened even if I had been there.
