Disposable or not? This is up to you. Disposable can make things easier for the recipient. Consider how important it is to you that you get your dishes back also. On the other hand, it is hard to find to a disposable container that can hold a large quantity of steaming stew. I tend to just take it in the pot in which it was cooked. Sometimes, the recipient will just pour it into one of their own and hand the pot back to me. But I don’t stress about my dishes. I have pots to spare and by and large my dishes have found their way back to me.
If you are taking the meal to a family that’s at a hospital and away from home, disposable would just be necessary. In that case, don’t forget napkins and disposable cutlery!