Some dogs just have to snuggle on their own terms. I think with time it may change and also if it is hot-that would be a good reason to not share body heat! Maybe when it gets cooler in the winter he will be more likely to snuggle!
I give Zelda face massages and she looooves it, she puts her ears back and pretty much falls asleep, and now she puts her face right in front of me when im sitting down and we snuggle. I also do leg messages which she loves and will rest her head on me. So try massaging him so it feels nice!
She isnt always snuggly though! I will go out of my way and sleep on the ground with her and i will start petting her and before i know it she will get up and walk away from me. Dogs will be dogs! If a human did that to me than i would be offended, but they have their reasons, and they are almost all the time valid!
Dexter wasn't a cuddler for the longest time. he still enjoys his time alone on the dog couch, but he loves cuddles now and will regularly come and sit his whole 69 lb self in my lap. Give Sabo some more time and be careful what you ask for LOL