Thanks for the replies and concerns everyone.
This freind and I exchange emails often and see each other once week. We aren't terribly close- we have recently met. As far as I know, her son is fine. Her emails haven't mentioned anything. The day after he was vaccinated(last week, a week before the temp drop), I was at her house, and she started telling me about how tired he had been since getting the shots the day before- she made a comment about how they really pumped him up. I carefully started telling her about how I've become concerned about vaccinating, and have stopped vaxing my kids for the time being, and we had a lengthy discussion about it... In the mean time, my friend had an ear infection and I emailed her some info about herbal remedies for that, which she didn't seem interested in... SO--- I didn't want to be an alarmist or interfere too much with her personal life unless I knew this was something really serious with the vaccines, so that's why I came here. Sorry to post such a long explanation!
About the temperature- she did a rectal temp- aren't those pretty accurate? I've never wrestled my kids down to get one myself. He was shivering and acting funny, but the house was warm. He was very cold. Also- my freind is not nursing, and I doubt her son would be taking any of those meds.
The thing that freaked me out about this was what if he hadn't waken up that morning- what if his temp dropped in the middle of the night, and never came back up before morning? My first thought was might this have been a brush with SIDS?
Anyway, thanks for all the help and concern. I'm going to bring it up to her next time I see her and gently ask her if she thinks the vaccines might have anything to do with what happened. Might get her thinking for future shots.