thing is my son has a bit of a BO problem - now I have asked about this before and was advised that I was not washing his clothes high enough
So I increased the temp to 60c which is fine for his work t-shirts but his 'best' clothes are a bit delicate to be washed at such a high temp
I use vanish in wash stain remover as well as the bio liquid on Mr P's clothes as he is usually very smelly.
If he's really struggling, maybe he should talk to his GP about it. I'm sure I've heard of folk having botox injections in their armpits to help with excessive sweating. Can be a very difficult thing to deal with.
I would suggest you experiment with the full range of biological tablets and find one that kills the BO and you like the smell of. You may find adding an extra tab gives you the oomph you need.
I can't see how stain removers and conditioners will help deal with the root of the problem, they will only mask the smell.
I wouldn't know what was "best". By the sound of it you want strongest at removing odours. In which case my usual choice of Fairy non-bio is probably in the wrong category. (I went to non-bio when I got fed up of the itching I was getting, but I'm unsure it made much odds. That said I itch less these days than I did, but I think it's probably something psychosomatic.)
Had been using a variety of liqui tabs but find they leave the washer stinking very 'fusty' after a while so have gone back to powder-Daz- and very pleased with the results.
Also once a month or so just do a boil wash and put about 1/2 a pack of washing soda in and nothing else no clothes, a lot of the smell in a washing machine is due to old decomposed fabric conditioner always make a point of cleaning out the conditioner draw with boiling water at least once a week.