Need help giving my best friend advice!

Samantha 🎣 • Mom of one bonus daughter👧 and 5 little boys 👶💙! 1 ceserian due to breech🔪. 4 VBACs💪 Married to my best friend.

My best friend is a guy. We've been best friends since grade school we are now 26. He's been seeing his ex for months now. He is crazy in love with her and wants to be with her. She knows this and wont say she loves him back (but says "I know you love me"), or commit to him, but she continues keep him hanging on. She tells him she cares a lot about him alot and isnt seeing anyone else but she "isn't ready for a relationship because she just got out of a bad one" (several months ago), hence she labels them friends. The two of them see each other regularly, talk on the phone constantly, spend nights with each other ocationally, and are sexually active. He gets aggravated when she makes plans without him (bars, nightlife), because he is fully committed and includes her in everything... Yet, she does her own thing. He has asked her if they are together and her response was "There is no difference in being together and what we are." But... she won't agree to deem each other "together"... I don't really know what advice to give him here. On one hand I want to tell him that they are not together and he has no say in what she does, but on the other hand I want to tell him if she really cared she would consider his feelings and thoughts in what she does. My husband told him to tell her to kick rocks, but if they arent "together" is she doing anything wrong? idk how to feel about this situation. What do y'all think?