I would always at least give a silent nod for hello and a smile when I saw DF'ed people. One guy later thanked me, said I was one of the few to even give him that much and he didn't understand it because we weren't really close.
A friend of mine was unbaptised disfellowshipped, back when they did that. I never stopped talking to him. I hid it from my parents. I'd go meet him and hang out (outside of our territory). We're still friends to this day.
Knew an elder who owned a cleaning company and had a DF'ed guy working for him (along with a lot of other JWs, mostly pioneers). They'd clean our building. I always talked to the guy. On the other hand, this elder wasn't treating him very well. The elder would always schedule him on meeting nights, ensuring he could never attend and get reinstated. I still think there was a conspiracy against him because he was messing around with another elder's daughter. Same guy who's car died in winter and he walked a mile in a snow storm to get to the Kingdom Hall, then got it counted against him for being late.
I'm trying to think now (it's been a couple of decades), I don't remember too many people who got DFed who ever stuck it out to be reinstated. Hmmm..., Maybe because shunning just doesn't work? But I suppose if it does, you've got some dedicated sheeple. All ready to recall tales in front of a circuit convention about how bad it is out in the world and to never make the same mistakes they did.