100% Brett - treat the same as a regular yeast; bottle when done! I use Brett a lot as a primary yeast and have had no issue bottling at 4 weeks (my normal schedule for everything except for hoppy ales).
Brett as a primary yeast acts the same as sacc yeast, and reproduces due to O2 in the wort, and finishes the same. Now if you add it as a secondary yeast and it undergoes anaerobic reproduction, it will keep working for up to 2 years and you have to 'assess' (or gamble) when the right time to bottle is.