I believe the issue is that Trump can't fire Watt or he'd have to go through the Senate to name a successor. If Watt stays on until his term ends in January then Trump can replace without Senate confirmation. So they can just wait him out.
But of course if Watt is on board with recap - he can be the one to start the process before he leaves. Kinda doubt they work with him though - or that he'd want to start the process before the Dems take control of the House in 2019. He'll likely do nothing on his way out.
Can't say Trump is allowing it to happen. He gets resistance everywhere and what is happening with the twins is playing out. So why get involved. He needs a good economy for reelection and his economy. The twins will assist in that mission and give the economy the kick in the pants it needs. Waters will do what she needs between now and June to get her name out there and any free publicity.