I think the point here is that if your DS doesn't like it, it should stop.
There are several reasons why this is wrong in my view when there is no medical or physical need for the assistance.
It's controlling - wanting to be supervising every aspect of someone's life including toilet use. We have to do this with tiny children, but not eight year olds.
It diminishes you DS's sense of his own ability and independence, and is making him more 'childish' than he actually is, - I think that is also about control - some people like others to be dependent upon them.
It's humiliating for your DS not to have his privacy respected.
Your DH maybe has a problem grasping that your DS is growing up and can do things for himself.
I would be concerned mainly about the toilet things. As far as bathing is concerned, I don't think there's anything wrong with the two of them having a game with boats or something when your DS bath - but only if your DS wants it. I don't think there anything terrible about a parent wrapping a towel round a child and giving them a quick rub dry whilst letting them do more intimate drying themselves.
He doesn't need your DH to dress him, - I don't think it's particularly weird, just unnecessary, and implies your DS is incompetent if it happens all the time (occasionally holding out PJ trousers so a child can get quickly into their bedclothes is not unreasonable though)
I think you need to sit down with your DH and have a word about boundaries.