
I know my beardies get a bit scraggly around 2-3yrs when the last stage of the adult coat is coming through.
As my breed dont get the full adult coat until they are around 4yrs. Maybe the TT go through a similar stage.
The soft downy hair is new coat coming through it will be a different colour .
My brown girls are born chocolate go through stages of brown until they end up cream at around 18m-2 yrs then begin to go brown again getting thier finished coat at around 4yrs.
A good spray to protect the coat is called 'the stuff' (from hub or petcetra) it stops mud and bits of tree leaves etc sticking to the coat and damaging it. Only down side is it can make your floor a bit slippy if you have laminate or wood floors so best to soak the coat outside and let it dry a bit.
Another grooming spray I love from dezynadog called amazing trix smells lovely too keeps the coat in good condition.
I know the TT has a different type of coat to my breed but I do think you are over doing the brushing .
another great product for behind the ears and the elbows is called cowboy magic you rub it in the coat where they tend to matt leave it for a few minutes to soak in and then gently tease out the matt.
HTH
Roni