I heard same from a colleague who's a Salford fan

He has been on some coaching courses away from Warrington. One time down under.
As he often tweets a few times a day, it's not hard to keep tabs on his whereabouts.

Briers was at all matches and training sessions and shared the role with Danny Fullerton on a fulltime basis.

Makes sense.

In a stable environment like Warrington there's not going to be much chance of unseating Tony Smith but ten games in to the season Salford are going to be won 3 lost 7 and Koukash will throw Iestyn Harris to the shark pool and promise the fans on twitter that things will better with 'Briersy'.

I checked with the elves
Briers isn't leaving Warrington
Continuing full time as under 19 head coach

Briers was nominally the assistant coach last season but he is the head coach now and has certainly been there for the start of pre-season. It is effectively a full-time position as the U19s train four times a week.

Disappointing if he does leave.