My two best friends are in a fight. One of them asks me not to talk to my other best friend which is in a fight with them. Do I either not talk to them because my friend asked me not to or do I talk to them.
Not talking to one of your friends would be getting involved in others’ fights, and taking sides. Unless there is special reason for it, you should certainly not do this.
Explain to your friend that you understand he has fallen out with your other friend, but you don’t want to get involved in the fight, and that you continuing to speak with your friends doesn’t of course mean that his friendship is any less dear to you.
Good luck and best wishes.