Hunter Biden’s defense team is expected to wrap up arguments in his federal firearms trial in Delaware on Monday, and the jury could begin deliberating by day’s end barring any dramatic moves — like a last-minute decision by Mr. Biden to testify on his own behalf.

Mr. Biden, who is President Biden’s son, was angered by the government’s tough cross-examination of his daughter Naomi Biden Neal on Friday and told people in his orbit that he would consider testifying. But the defense, after a weekend of consultations between Mr. Biden and his lead lawyer, Abbe Lowell, now seems more likely to rest without taking the risky step of putting Mr. Biden on the stand.

Prosecutors and Mr. Lowell’s team will meet early on Monday with the presiding judge to consider a request by the defense to dismiss the case.

If the judge, Maryellen Noreika, rejects Mr. Lowell’s motions, as expected, each side will present its closing argument and Judge Noreika will issue instructions to the jury.

The government has sought to show that Mr. Biden regularly used drugs in 2018 and 2019 and that he falsely claimed to be drug-free when he filled out a federal firearms form. His lawyers have offered a spirited, if narrower, defense centered on whether Mr. Biden was actually doing crack cocaine at the time he bought the gun in October 2018 and have sought to undercut the prosecution’s witnesses by challenging their recollections.

Over two days, David C. Weiss, the special counsel in the case, summoned three of Mr. Biden’s former romantic partners, all of whom described in painful detail Mr. Biden’s unrelenting descent into crack addiction after his brother died of brain cancer. They included his former wife, Kathleen Buhle; a onetime girlfriend, Zoe Kestan; and Hallie Biden, his brother’s widow with whom he had an ill-fated romantic relationship.

Ms. Biden Neal has thus far been the only woman called by the defense.

In emotionally raw testimony, she gave an upbeat assessment of his drug use in the weeks before he bought the gun, saying he seemed “hopeful” and sober.

But under cross-examination, that claim seemed to crumble, with prosecutors introducing text messages from that period that illustrated an anguished, and excruciating, relationship in which she informed her father he had driven her to the breaking point.

Still, Ms. Biden Neal could offer only limited insights into the actions of Mr. Biden, who was often absent from her life for months and erratic even when they were in the same city.

The prosecution, which rested on Friday morning, has also pointed to hundreds of text messages and bank records, as well as to the defendant’s own words, to illustrate Mr. Biden’s unyielding drug addiction in the months before and after October 2018.

Over the last week, Mr. Lowell has established that no one saw Mr. Biden doing crack cocaine in the month he bought the gun. Ms. Biden Neal’s testimony did not change that.

But two text messages retrieved from Mr. Biden’s phone have hurt his defense from the start. One day after he purchased the gun, he sent a text saying he was meeting a dealer named Mookie. A day later, he followed up to say that he was sleeping on a car and smoking crack.

The apparent admission came to a head on Friday as Mr. Lowell questioned the prosecution’s last witness, Joshua Romig, a special agent with the Drug Enforcement Administration, who was asked to translate drug lingo introduced in the government’s case against Mr. Biden.

Mr. Lowell made the point that while the prosecution had spent days examining Mr. Biden’s communications from earlier in 2018 and 2019, showing pictures of him holding a crack pipe and texts about buying drugs, there was nothing comparable to show for October 2018.

“No reference of Chore Boy?” Mr. Lowell said to Mr. Romig, referring to terms related to crack use. “No mention of a ball?”

Mr. Romig responded, “With the exception of the October text that we talked about, where he said he was smoking crack.”