OP, I'm now wondering where you (or your sister live) as there is a woman and her DS who sound very similar living locally to us.- actually, it can't be the same one, as this boy is now 8.
The DS has had a feeding tube inserted for about 3 years, because of an underlying condition, but can eat normally, but this causes more problems, hence the feeding tube.
He has a suppressed immune system, and is very susceptible to chest infections, and has spent an awful lot of his life on AB's.
He is still not potty trained due (found out this year) to some bowel problem that was very dificult to detect - something to do with nerves I think, and he is likely always to be incontinent.
For years, his mother insisted something was wrong with him, but doctors wouldn't listen - she ended up seeing the doctor every day for weeks before they finally sent him for tests, and found she was right.
They also found some autistic spectrum disorder (?) and found that mainstream school was fine, but he did need one to one to help him with social interacting etc.
The mother went through years of vicious gossiping, endless referals to SS, well-meaning strangers in the street telling her to stop ruining her DS's life and just enjoy him.
I know you've now reported this, but I think this is unfair, as you don't know anything about her, or her son. Gossip isn't always right.