Honestly OP, if you have a runner, it’s pretty hopeless I know. He sounds very bright. This stage, where they are fast and hell bent on escaping, but don’t have any fear, is absolute hell unless you are giving him one to one attention. I’d say that’s exactly what he needs …one to one attention ….in an ordered environment.
Your DH has to step up at weekends. It’s easier if you are a team and you aren’t a team right now as you say he doesn’t even know what you are going through. So you need to tell him.
DH needs to be playing properly, with full attention on your two year old. He needs to build the tower over and over again so the little one can knock it down. Not just once, twenty times. He needs to calm him with books. He needs to practise walking with him on the street. He needs to chase him round the garden. He needs to talk talk talk to him, sing with him. He needs to push him on the swing till his arms ache. He needs to build dens indoors and outside, climb trees, jump off logs, help him learn to scoot, swim and kick a ball. He needs to dance with him, play-wrestle with him, rake the leaves with him, gather apples with him, wash the car with him. While doing this, he needs to really observe and understand his needs and likes and think of ways to meet them until your son is calmer, instead of frantically searching for stimuli. He needs to show his son how to relax with him on the sofa for a minute or two in between activities. He needs to get down and show your little one how to play with his toys at home, talking all the time, building a proper father son relationship with him.
Your son is able to stick to routines and do most of this at nursery so he can do it at home if the framework is there.
Your DH needs to give you a break, even if it means taking time off work.
Your in laws could be less judgemental and more helpful/understanding. That’s also on your DH to sort out.
Your own mum …could she take the four year old for a couple of hours, so that you can give your two year old some really intensive play time where you are fully engaged and reaching him on his level, playing the way he wants to play.
As for food, stick to the rule of eating meals only at the table. Get a child size table if you haven’t already. Eat with them. The food stays on the table. There is no walking around eating or walking round with a bottle. There is no food in between meals. Eg… Breakfast, snack, lunch, snack, dinner, bath, milk with a story, bed. Offer it nicely and present it attractively to them. If they don’t eat it, put it in the bin. If they throw it or drop it on the floor, put it in the bin. But if they need to handle it before eating it, that's ok. Crumbling a muffin is ok as long as they then attempt to eat it too. Try never to stress about food. Take the little table outside. Let them eat outside for a change of scene. But stick to the rules.
Don’t try to talk or reason when he has a tantrum. Put him in his bedroom if possible with locked windows and the door ajar. Sit outside the door so he knows you are there. Take a breather while he screams it out. Think about what started it and if there is a pattern emerging. Maybe read a book with your four year old. Then give him a hug when it’s finished and move on to something nice.
Tonight when they are in bed, put some toys away so they can’t make as much of a mess. Keep the books and favourite toys/puzzles and building toys in a designated place so they get to know where things belong. Play the cleaning up song and show them how to put things back in the storage boxes. Enjoy doing it yourself until they want to join in. Show them it’s fun.
In your distress, you have lost a bit of authority and willingness to engage in fun play. I’m not surprised at all that you are struggling if you are doing it all alone, as well as working.
You are crying out for help. If I lived next door, I’d come and help you.
You are a good mum. Asking for help isn’t easy .
This stage will pass OP. But do let your DH in on how distraught you are feeling.