One possibility is to process the film first in black & white. Even if the film is in very bad condition,, you could possibly get at least some images out of it. It is possible to process the color film after this by bleaching, washing, re-exposing with light, and then processing it in C-41. But if color processing is done first, and it fails, there is no way to try recover anything any more by processing it in black and white. What kind of action is the best, depends of course on the age of the film, and hoe it was stored. In general, colot films exposed long (decades) ago, but not developed, tend to keep quite poorly. In practice, these methods often need digital scanning and quite heavy digital editing to get anything goof out of very old films exposed long ago. I am no way expert in anything digital, so there is very little I can help in this part of the process.