If there was going to be a deal done with Philadelphia that would be some form of an iteration of Brown for Simmons, it would have been done months ago.
Boston isn't trading Brown for Simmons. They might trade for Simmons, but Brown would never be included. Philly has been holding out for a young all-star caliber player and picks and no one is close to offering that.
Portland isn't offering McCollum or Lillard
Toronto isn't offering Siakam or VanVleet
Boston isn't offering Brown
And on and on.
The market for Simmons is drying up because no one wants a recalcitrant who hasn't gotten better after 6 years, can't and won't shoot three pointers and who's free throw shooting is so bad, you can't play him in the 4th quarter of close, important games. I am sure that choke pass that cost the Sixers a playoff series is still dancing through the heads of front offices across the league.
If Boston does a deal for Simmons, it does not include Brown. Smart, yes. Schröder, yes. Hernangomez, yes. But not Brown.