I'm an old lurker with a new screen name. I logged out a few months ago and while trying to log back in I seem to have forgotten the password to my old account. 
The few months I have become increasingly annoyed with my PIL.
Of course there are small issues before but nothing major. Mostly just MIL being dramatic and a gossip which isn't a huge deal to me and I can deal with it. She's been mostly helpful.
DH and I have a 3 year old son who has epilepsy. Under the recommendation of his doctor we have started him on a ketogenic diet. That is a high fat, low carb diet which means he can't have any sweets with regular sugar. He has been on the diet for a month so far and it's going well.
We talked to MIL & FIL when we first started about NOT leaving out food out if they knew we are coming over. They acted like they understood and were okay with it.
DS can't have foods that "typical" kids eat.
On this particular occasion, DH calls to say we are on our way.
When we walk into their house, there are freaking cookies sitting on the stove. I know we should have asked them to make sure all food was put away but we thought that was understood since we had that talk.
DS sees them and cries because he wants one. PIL "forgot" and are
"so sorry". We forgave them because it's a change and they have to get used to it.
After that we gave them a booklet about epilepsy and the ketogenic diet.
A week later just DH takes DS over there to see them. I had packed DS's lunch to take with.
Apparently, MIL sees what I made him and according to DH she says in a disgusted tone, "What is THAT?"
DH told her this is how DS eats now for his health and not to act grossed out in front of him.
It wasn't even anything bad. But for MIL "healthy" is frozen chicken nuggets and sweetened applesauce.
A few days after that, DH and I go over there while FIL is at work for DS to play with his cousin who MIL watches.
While DH was using the restroom she makes the comment, "(FIL) saw what you packed for DS's lunch the other day and he asked "what on earth is that!"
(She was the one who said it, but made it out like FIL was the one who said it? Really weird.)
Anyway I responded the same as DH, "Well that's DS's diet now."
While we were there (I packed DS's lunch again) we were all sitting down eating lunch. DS's cousin wanted chips and a peanut butter and jelly sandwhich (he's the same age as DS. Eats
nothing but junk all day.)
DS was eating his food. The cousin and MIL were both looking at his food and had grossed out looks on their face. There was also some issues with DS being upset that he didn't get what his cousin was having so we will no longer be taking DS over there during eating times, because it's not fair for him.
A couple of weeks after that, DH takes him over there for a visit again.
He calls ahead to make sure all food is put away. Cousin isn't there this time.
While there, DS finds a random sucker in their living room!!!
MIL had NO IDEA where it came from. DH said he asked DS where he found it and DS said in one of the table drawers but MIL claims to have cleaned them all out.
DH and I have agreed that we're not comfortable with taking DS over there anymore.
Are we being unreasonable and mean or is this the right thing to do?