Man, it really leaves a bad taste but if you think about it they werent all that good friends anyways, Maru and Isami's were in there pretty much for the money, and Tobio stuck with it because of his guilt which is what he does, even with his girlfriends he stays with them to bury his remorse by having good times, in that sense
@magma6 it doesn't matters much if the baby is not his, the excuse of making a family is just as good as all of his other superficial relationships and serve the same purpose it is a way to put his consciousness at ease, and finally there's Paisen who never managed to make any connection with anyone and on top of that is being shunned by his former pals i guess i would call them.
I don't know i want to think that at least Tobio is his friend and he was not there just out of desperation to seek atonement for the bombing, but the last 2 pages tell me that this is exactly what he does.