Is there anything you can do to fix this?

[Tom Dulski]

 
Once this happens to a favorite brush is there any way to get it’s bristles to go back together?

[Elbows]

Brush soap, but realistically not likely.  Just remember, a favourite brush should only be $3-5 and they're consumables

[Hitman]

Sadly, I agree. But you can extend its life a little longer by using it as a dry brush. I just had to do it to 2 of my favorite brushes. They painted several hundred figures for me...😥😢😭

[Cubs]

Brush soap might help, but then you've got paint in the ferule like that, I find a little swish about in some pure acetone releases some of the build-up. Don't do it too much or the glue will dissolve, too. Also, much as people say not to do it, I use saliva (or wet soap) to taper it back to a point. But once the bristles begin to split like that, it's not really reversible, the best you can do is try to manage it.

[zemjw]

Have a look on YouTube,  as there are loads of videos on restoring brush tips. Hair gel seems to be mentioned quite a bit, although my one attempt at that failed miserably 

[Tom Dulski]

 Yeah I saw a few things on YouTube, one video said to use hand sanitizer and that did not work and another said rubbing alcohol and that also did not work.

[LoxIslay]

No hair gel but wax! Works fine. First soap it clean, then put a bit of wax on it and refine the tip with your fingers. Brush can be damp for that.