This is not a slight case of hypospadias, which is easy to discuss because there is no reason to do anything at all. The boy just has to move his penis this way or that to get his aim right. Or, like my husband, who experiences pain from adhesions when he stands to empty his bladder, can sit down to pee (a relief to any wife when it comes to bathroom smells and cleaning). Some men, like Dr. Dean Edell, who talked about this on his radio show, sit down to urinate because urine splattering isn't hygienic. It's no big deal for a male to sit to pee. Lots of men do.
This boy's hypospadias is more remarkable than a slight displacement of the urethra. They say boys heal better from this surgery when it's done early. However, if it was my son, I'd think long and hard before I allowed the surgery because I am aware of the harm. Tiger Howard Devore was born with severe hypospadias and has experienced over 20 surgeries and four full reconstructions. He says that, "all the surgeries I suffered up to age 19 were unnecessary failures."
I would talk to my son about the acceptability of sitting down to urinate when it's age appropriate and tell him that, when he grows up, he can decide whether or not he wants surgery performed. My guess is, if he's alive, he's urinating one way or another, and if he is, he can keep on doing that until he can make a personal decision about his own body.
The best you can do is tell the boy's mother that, if she's considering surgery for her son, to get several opinions and to ask to see before and after photos… and to learn long-term outcomes before she says yes to letting anyone take a knife to her son's penis. Perhaps she can contact Tiger Devore through the Internet and ask his opinion, although don't we already know what he'll say?
This is no small thing and surgery is painful, traumatic, and, as in Tiger's case, may not be successful. I think the rates of complications from the surgery often are simply not discussed. My concern would especially be starting my son down such a road, with potential problems and difficulties being a very real and present danger.