For me, it's not so much soft as slippery foods - to my great surprise I found out that by six weeks post radiation, I could eat rice crispies with lots of milk, while any kind of cooked cereal was impossible. Keep trying different things, as everybody says. Chinese buffets are great, you can try a little bit of lots of things, and go back for what works - just avoid the spicy stuff - and a lot of things are slippery.
Often thick drinks, like milk shakes are easier than water or juice.
Good luck, Leena