Toddlers diarrhoea ADVICE!!

Hi all I’m looking for advice not negative comments.

** TMI post ***

My 15 month old Marcus was has had a very nasty belly since last Sunday.

Back and forth to the doctors and sadly hospital on Friday, to be told it’s called “toddlers diarrhoea” (i thought they’d made that up).

It’s sparked by either a poor diet or being given something that a person could be intolerant too so in marcus’ case cheese. (He was given cheese on Saturday by my mother in law- we’ve had words)

We’ve been told by Doctors that it can last between 10 days and up to a month.

He pooes pure gritty water / yellow mucous poo and none of it is solid.

We are still awaiting stool results for him which could come back as late as Wednesday this coming week.

Everything he consumes just comes straight out.

Been told rehydration salts do not help him, but just to do the BRAT diet and treat it like an upset stomach...

But still to no change or joy for him.

Has ANYONE else ever had a child or maybe heard of this that can offer some sort of advice.

Awaiting his dietician too but been told it could be as early as January 18’

He’s lactose intolerant and drinks Alpro Growing Up milk 3 bottles a day (been told to continue with this as its soya)

Thankyou.

Just feel so upset and sorry for him.