Yes he can. The president has almost total executive power. He is also in the process of making political appointments in agencies that have traditionally been staffed by non-political career civil servants. Just look at the purge he is running on the FBI at the moment, clearly with the aim of staffing it with loyalists who will act as his Praetorian guard.
He can and will ignore court orders. He has appointed a loyalist to lead the US Marshal Service who are tasked with enforcing federal court decisions so clearly no court decisions will ever be enforced against him or his cronies.
He will ignore the congressional appropriations process if it goes against him and fund the government directly from the Treasury.
The checks and balances in the constitution have no teeth.