So with chapter 393 we find out that Silver is indeed Gray's father NOT Deliora, but at the end of the chapter Silver's death is now foreshadowed. Now I personally don't want him to die, but thats just wishing, I have a few reasons to believe that Silver is not going to die.
The first reason is that Hiro Mashima never kills a character whose death was foreshadowed (e.g Wendy(Tartarus), Gray(Galuna and Tartarus), Erza(Tower of Heaven), Rogue(GMG) etc). Now some may say: "Oh but Lumin, Mashima has killed characters before, its the same for Silver, hes gonna die now." Now that's not always the case cuz he trolls everyone, and also when Mashima kills a character he just straight kills them, he's not waiting(ex. Simon, Old man Rob, Zancrow, Azuma, Future Lucy, Gray(when he saved Juvia from the hatchlings)) So if he wanted to kill Silver so badly he would have done that awhile ago. Now don't tell me that hole in his body will kill Silver because Sting did the same to Genma/Jiemma before and hes still alive and kicking and the hole was much bigger and more impactful.
The second reason is that Silver can still be used for development such as Gray's character who may learn Demon Slaying Magic(As said by many) or he could help gruvia become canon(that moment in 393.. yeah..) or he could "repent" for his "sins"(What did he did he say he did wrong again?) by joining Crime Sorciere and repenting there I mean Jellal still has to show up and all but still he could join(Btw Mashima where is Jellal! We've waited long enough for him). Also Silver could be a comedic use too, I mean his son is a stripping tsundere who has a semi-stalker girl obsessed with him, he could say so many things to Gray about that in a comedic form.
Now having said all of this, I still personally want Silver to be alive because I feel as if Gray has been bashed by his past one too many times throughout the series(Lyon, Ultear, Ultear again, Silver) but this is still personal thing. I hope my reason were at least somewhat legit in a way. So tell me what you think about my theories/reasons(I don't know how to make poll sadly)