The fact that Ignis just keeps on walking until he's standing right next to him should give Ravus a clue about his plans for the evening. Although, even if he did have some, he could always find some time to spare for him.

He has seen it, which is why he knows how much today must be hurting him. If only he knew proper words of consolation to offer- but nothing that can be said can excuse the early death of young Oracle.
Would talking about her help him? Or just wound him further? The questions of 'what if' and 'how was she'. Perhaps. But... maybe Ravus does need to talk about it. About those "if's".

"I am sure she would've loved to spend her birthday with you," Ignis offers softly, eyes slipping from Ravus' profile and onto the sea and slowly setting Sun.