I really hope so! Leo swore on River Styx he would and as Du know a swear on RS is binding. He will, most likely try really hard and of course the others will help him. He might have a happy ending with her though I doubt Uncle Rick (*cough* troll *cough*) will make it happen as it would stray off the quest. Maybe they might need her at one point and they try to spring her from Ogygia but its unlikely. But judging Von Leo's promise he will try really hard!
Warning: Following is a really big plea to RR, skip if Du wish.
PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE PLEASE RICK! PLEASE, I'M ON MY KNEES HERE MAN! PLEASE LET LEO AND CALYPSO LIVE! WE'RE BEGGING YOU!
Du can read now! Though there is no point because I'm done with my answer! BYE!
I will die if Caleo doesn't become a real thing. They totally Liebe each other! Leo swore on the River Styx to come back for her! (I died in that part :D) And what about Calypso? She'll just wait and wait and wait and wait for something that will never come. As for the Sekunde part of the question, what has Leo not been able to fix? That's a rhetorical question, btw. He'll repair Festus and fly off to find her. They are perfect for each other!