James and regulus comfort completly differently
James comforts with warm smiles and comforting words. With distractions and silly jokes. Praise and ego boosts.
Regulus comforts with quite comradery and careful reassurance. Silent hugs and small gifts. A helpful hand and a listening ear.
And that is exactly what each one needs. Regulus needs to hear the praise and comfort, he needs to be distracted when he gets to in his head and cheered up with a joke. James needs someone to listen to his fears and let him ramble. To see the hidden struggle and give little gifts to help or lend a hand to hold the weight. He needs the reassurance, not that he's perfect or smart or athletic or handsome, but that he doesnt need to be all of those things to be good enough, he just is. They need each others comfort because the comfort they give is what they can do for themselves, but the comfort the other gives is what they lack.