What is the ruling on traveling to visit an uncle and a father buried in an unlawful graveyard (rooms where the deceased are placed one on top of the other)? Is this considered traveling to visit graves? Is it permissible to visit such graves, knowing that the uncle will be saddened if he is not visited?

If the travel is to visit the uncle, there is no harm in it, and it is not considered an act of "preparing for a journey" to graves. Visiting the father's grave is included incidentally. As for visiting the father's grave there, there is no harm in it, whether the graveyards are permissible according to Sharia or not, because accompanying funeral processions and visiting graves are not abandoned due to an innovation or an evil act committed by others. If there is an evil act, it should be denounced and removed if possible; otherwise, the truth should not be forsaken for falsehood.