Table manners

Personally, for larger meals, I prefer to combine everything on my plate, so every mouthful tastes and feels the same. I also like meals that do this naturally. Since my diagnosis, I don’t worry as much about my urge to mash everything together at home.

My plate of pie, veg, roast potatoes, and gravy looks like a pile of mush! I do stick to "polite" ways of eating meals like this in wider company (ie I mask). Even so, I get told off my by partner for rearranging things, between mouthfuls, to be positioned "just right" (in my view).

But I do always eat toast or sandwiches with a knife and fork, wherever I am. And I split larger sandwiches apart, into two open ones. No one has ever seemed bothered by it.

Autistic eating behaviours can be driven, for example, by sensory differences (which is why I eat those and many other things using cutlery):

NAS - Autism and sensory processing

Also, as the NAS also explains:

"Attention to detail, and difficulty with change, is characteristic of autistic people. The way the food is presented or positioned on the plate, or the food's packaging, may dictate whether it is eaten or not. "

NAS - Eating

NAS75657 said:

Should I teach him to eat it all together for when he’s eating out or in someone else’s home? 

This would be asking him to mask, which can have detrimental impacts (eg distressed behaviour, mental health issues), including over time. You might find this article helpful when considering your question:

NAS - Masking