Tattooed the name of his wife and his three kids.
Had five kids?
You're the left out kid?
Don't get it.
Three and one don't make five; they make four.
Who are you leaving out in the middle of your hurt, and why?
Got it that the old man is a real piece of work with serious loyalty problems and really serious memory problems and really really serious problems understanding his obligations to others because he comes first ahead of children, prior family obligations, what feels good, resentments and banks, if your poem is any indication.
If you choose to revise, and this poem is good enough as is, so you don't really have to, you may want to tackle the things that may come up in some readers' minds as a result of your method of tackling this version, which, as I say, is more than good enough: Who is this other kid? What is the writer's relationship with this other kid, or does this other kid even exist for the writer?
If not, then some subtraction might be called for in the original text to keep the focus purely on the rage and resentment that the writer feels for the dork of a dad. Why split the reader's attention, really?
The nature of a lyric is such that it helps to keep the reader focused on a single thing, and your poem would be improved by helping your readers keep that focus.
Yes, it's clear you worked hard and the work is paying you back. I would hope that other people like it; there's a lot to like about it.
Sincerely, Bob Kaven