Oh good for you OP, it does sound like your DF has been stirring!
The thing is In Laws (and others tbh) can be irritating, the relationship can be difficult but its your own emotional response to that which dictates how things are going to be.
For example my MIL is a HUGE help to me, I love her to itty bits but my good god can some things wind me up. I have to just decide what is and isn't important. So shoving the DCS mouths full of chocolate the second they cry I hate but let go because I figure its not harmful if they don't get the same message / overfeeding from me the majority of the time.
However the constantly running kettle and rice cooker was on a toddler head height table and my foot came firmly down and I very sweetly said it may be me being fussy but I heard of "x" child who had been burned this way and the DCs just couldn't come over if the kitchen weren't rearranged with heated items on a higher shelf. I had the conversation with MIL, SIL and DH and the kettle and rice cooker were relocated. Problem solved.
However other SIL (BILs wife) took little issues and reacted to the nth degree, never said anything directly, always via BIL, always saw things as a battle to win / a way of offending her and the whole thing snowballed until everything was a drama, PIL started acting the same way and they are barely in contact. I see how torn BIL is between wife and family and how worried MIL is about never seeing his DCs and it was all so avoidable with better communication.
Aim for the happy middle ground most of us inhabit, you may not be best buddies and agree on everything but as with all relationships you forge a way forward that satisfies all parties on the whole with lines in the sand when things are dangerous (eg grapes) Vs irritating e.g snacks / apartment location.