Joel is alive !!!!!!! why ??? well let me tell you what's going on, I might be wrong but I guess what I'm thinking is right and correct, she could shot the Joel but she didn't, just a hit on his head didn't mean he's dead if she really wanted to kill him why did she tourniquet his leg after shooting it? they wanted to leave the town as soon as possible and they let go, Tommy and Ellie, now as Tommy, he needs to hide his brother and make a fake grave for him that tells everyone, leave my brother Alone you wanted to kill him here you go his grave ( fake grave ) to keep his brother safe. now Tommy didn't want to tell something about it to anyone cause that was crucial in order the keep his brother away from all possible trouble.
and till the end, Tommy wanted to kill all of his brother's enemy but Ellie wanted to take Joel's revenge.