Bunny-sitting rabbit with a tilted head

Ok so my sisters boyfriends family has gone on holiday for a week and asked me to look after their rabbit Nibbles for a week. The told me that he had a stroke a while back, and his head is tilted, but when they arrived with him earlier I was shocked at how tilted his head is.
Apparently he did have medication when this first happened, but not any more, he seems to be eating and drinking fine, and seems to move around fine, but I've never had any experience with this before in the years ive kept rabbits, so I was wondering if there was anything I can do for him the week he is here? Any advice would be amazing!

Don't worry, my bunny had a stroke and was paralysed on his right side. It is amazing how quickly they adapt, and it is brilliant he is able to move about and feed and everything himself. That is right that he would be unlikely to be on any meds now, but honestly it is nothing to worry about, just keep an extra close eye on him, that's all. It does look very uncomfortable though doesn't it, and you wonder how on earth they can manage with their head like that.

Roger had a terrible head tilt, but fortunately I was off work sick at the time and put so much work in on it, some days up to about 8hrs of what I called his physio, massages to stop the muscles contracting and everything shifting, therefore keeping his head in that position, and I managed to find some tiny cushion things that you could warm in the microwave, and then lay against Roger's neck to keep the muscles warm and supple. To everyone's amazement, he made a complete recovery and I managed to completely reverse the tilt, and you couldn't see it at all, but I think that was helped a lot by being able to work on it so intensively when it had just occurred and before everything shifted.

Thanks for replying, I'm glad it's not anything I need to majorly worry about. When they first bought him in all I could think was, how can that be at all comfortable or ok, but hes been here for nearly a day now, and he seems ok apart from the fact he looks a bit funny.
Im not sure what his owners have been doing in terms if massaging his neck and stuff, but I'll definitely give that a try whilst he is here if it makes him more comfortable, thanks for the advice