Alphonse really did love his older brother. In fact, Alphonse held Edward in such high regards that the younger sibling dare promised that he would do anything for his brother. Anything.
Ed was all Al had left and if he was gone Alphonse couldn't possibly think of any more reasons on why he himself, should continue living. Of course Alphonse had thought of Winry, and Auntie Pinako, and the Colonel and the Lieutenant and the various dogs and kitties he had rescued over the years, but none of that compared to the bond that Al had established with Ed over the many years while the two grew up.
Al wanted his body back, oh yes, he wanted his body back real badly but he would see to it that if the Gate only allowed one of them the privilege, that it had to be Edward, his beloved brother. His brother definitely deserved it, working so hard for the both of them and making so many sacrifices along the way. And even though Alphonse knew that Ed would reprimand him for his ideas and that Ed would most obviously volunteer himself for Alphonse in times of need, Alphonse had experienced this first-handedly, Alphonse would see to it that he would be the one to help his brother out once in a while.
The both of them had been through a great deal of pain and Al thought himself lucky that his weaknesses wouldn't be exposed since his armour body was incapable of showing emotion. Even though he secretly wished that would be able to cry again he enjoyed comforting his older brother in times of need. But Al knew that Edward didn't like to show weakness and his soft spots, his brother was a knuckle-head more often than not, but Al knew better than anyone else that Ed was the most sensitive person out there, even more sensitive than himself. Al saw his secret tears and heard his muffled crying at night and it made his heart hurt. Although it was then that Alphonse could truly feel the pounding in his steel chest for a split second, bathing in the humanness of it all and it was then that he realized there still was hope.
Edward liked to do something that Alphonse had dubbed the two-in-one action. He ate both of their portions when they had meals, 'don't worry Al, we'll make sure you eat this when we get your body back.'
But most importantly Edward cried for the two of them. He cried for himself and he cried for Al when Al himself couldn't cry. It made Alphonse feel happy and special inside, and when Edward cried for him, he felt the tears roll down his own cheeks.
Edward became Al's skin, his own touch, his nose, and his senses. He described the smell of the chicken pot pie or the stew that venders sold in markets. He described the feeling of the morning fog on their skin and the dew in the grass as they trekked their way through country roads. He described the feeling of a paper cut and how furry Alexander felt or how the shower was really too cold in their inn. He described the smell of the sewer and the garbage that was left at the side of streets. Al could see the flies buzzing around, could hear people yelling, but he just couldn't feel, he couldn't sense and Alphonse felt indebted to his brother in a huge way, he truly was thankful.
Alphonse couldn't sleep, didn't sleep, even if he wanted sleep he couldn't get it. He would generally just doze off in his own head full of imaginary thoughts and day dreams for the night and that was like sleep to Al, it was the closest thing Al could get to sleep anyways. Sometimes Al would day dream so far into his head that he wouldn't hear anything around him for a short while and Alphonse would experience that short sleeping sensation. One time Al was thinking real hard, it was about Scar and the (then) recent murders of the State Alchemists and trying to protect Edward since his brother really could be stupid sometimes.
He was just thinking of ways to beat the 'need-to-keep-living' idea into Ed's head when he noticed that he had a blanket over his steel body. He couldn't feel it but he saw it. The dark blue, woven texture that he couldn't feel was laid over him like it could keep his body temperature the same, if he had one. Looking over Al remembered seeing Edward sitting there with a contemplating look at him, when Ed finally saw Al he smiled, "it's cold tonight."
Alphonse could suddenly feel the blanket; he had never felt something so soft in his entire life.
The days went by faster and faster, some days found the two brothers in the library reading all day while others were days that were filled with yelling and running. Al was secretly glad that even though he didn't have a body and that Ed didn't have his arm or leg, that their journey would be filled with so many valuable things learned, lost, and gained. And to be able to share it with his dear older brother? Al was the luckiest person alive.