Frubsdad, I think you need to talk to the parents/in laws and tell them while you appreciate that they are trying to help, you are THE parents, and you are doing everything humanly possible, and the constant suggestions undermine you rather than aid you.

I put together a little card with the definition of SPD and how it presents behaviourally, which I printed out and laminated and handed out to the in-laws and my mom and sister-in-law. I'm not sure it really helped, but they are asking more questions and make less suggestions ;P

I'm not sure about a specific brand of weighted blanket. We are having one made by a seamstress, it works out a LOT cheaper than buying online, in S.Africa the difference is R150 (seamstress) vs R800 (online - excluding postage). I'm not sure if you could get something at a comparable price where you are, but I'd give it a try.

As far as I've seen with the copious amounts of reading I've been doing since our boy was diagnosed - the ebb and flow is a characteristic. One story I read (maybe here, maybe somewhere else?) said a little boy was driven to distraction by a loose tooth. He was much better after the tooth fell out. It seems like just about anything can set them into a high-tide kind of patch...

I wish I knew the answers... I really do- for you and me both! I read and read and there are so many things that claim such amazing results and blogs that say this is the one, this is the *cure*... in general there seems to be a common theme that anything that works the brain, especially in ways that promote rythm, timing, and co-ordination between the halves of the brain, is likely to have a good effect. Interactive metronome, Brain balance, Brain Gym, there's another to do with neuro-music therapy I think.
I'm waffling, sorry. I think what I'm trying to get to is - if it's at all possible, can you try enrol your son in music classes(kindermusik maybe?) or Brain gym? I think it might also help your wife to get out during the day. In my unprofessional view, it sounds like she's a little depressed, and might benefit from some adult interaction and getting out and talking and interacting with other people on a regular basis while someone else is working with your son - it's less formal than counselling or OT, and more social.

I'm really so sorry you're having such a hard patch and can only hope things take a turn for the good again soon.

Oh - we're trying to find out if the Feingold program is available here, but I really think it could be beneficial for anyone and everyone to get off of the nasty colourants, preservatives and additives. It can't hurt... Not sure where you're based (sorry if I already asked!) but if you're in the USA I think it could be worth trying? LAC has recommended it a few times, so might be worth checking with her