Witnesses do not shun family members because of differences in religious beliefs. Many Witnesses have religiously mixed families and enjoy normal loving relationships together.
A classic strawman argument. This isn't the issue being addressed.
As far as JWs being DFd if they associate with DF people , I suspect that this is rare. The instruction per the elders book is that they won't be given any privileges (or would be removed). They could also be marked. In reality , JWs who do associate with DF ones tend to be quite circumspect about it. A relative of mine was DFd for remarrying when not being officially "scripturally free" to do so (we suspected her JW ex-husband had been unfaithful but he denied it & nothing could be proved.) She had to wait the usual 9 months or so until she could be reinstated. During this time the family had quite a lot to do with her and some even went away to Center Parcs with her on holiday. The elders were ( kind of ) aware of this but turned a bit of a collective blind eye.