The son of a Canadian-Iranian academic and activist who died under mysterious circumstances in an Iranian prison says he鈥檚 鈥済rateful鈥 to the Canadian government for trying to help his mother who has been barred from leaving Iran with no explanation.

Mehran Seyed-Emami told CTV News Channel that his mother, Maryam Mombeini, was prevented from boarding a plane in Tehran, Iran and her passport was confiscated when she tried to accompany him and his brother on a flight to Vancouver earlier this month.

Mombeini returned to her home in Tehran while her sons arrived safely in Canada on March 8.

Although Mombeini has dual citizenship, she has not been able to receive consular assistance because Iran doesn鈥檛 recognize dual nationals. Her sons have said they believe Iranian authorities are preventing her from leaving the country to intimidate them against speaking about their father鈥檚 death.

Kavous Seyed-Emami, an Iranian-Canadian sociology professor and environmental activist, was arrested on Jan. 24 in Tehran on suspicion of espionage. The 63-year-old academic was held in Iran鈥檚 notorious Evin Prison for just two weeks before Iranian authorities announced he had killed himself.

The family has publicly questioned the Iranian government鈥檚 explanation of his death in addition to the accusations against him.

Mehran said he spoke to his mother on Tuesday morning to send her well wishes on the start of Nowruz, the Iranian New Year. He said she is still reeling from the death of her husband and their separation during the holiday has been difficult for her.

鈥淪he鈥檚 obviously heartbroken. She鈥檚 trying to stay strong because she doesn鈥檛 want me and my brother to worry about her, but it鈥檚 our immediate concern to get her here as soon as possible,鈥 he said on Tuesday.

Although she has received no word from the Iranian officials about why she was barred from leaving, Mehran said his mother has been comforted by the Canadian government鈥檚 vocal support.

On Monday, Foreign Affairs Minister Chrystia Freeland issued a statement calling on the Iranian government to allow Mombeini to return home.

鈥淐anada is gravely concerned that Maryam Mombeini鈥檚 travel ban was not lifted over the weekend. We continue to call on Iranian authorities to immediately give Maryam Mombeini, a Canadian citizen, the freedom to return home,鈥 the statement read.

Freeland also said they would continue to demand answers from the Iranians on the circumstances surrounding Seyed-Emami鈥檚 death in custody.

Prime Minister Justin Trudeau reiterated the Canadian government鈥檚 position .

鈥淚ran must allow Maryam Mombeini to leave the country and travel to Canada to be with her family - and the regime must provide answers in the death of her husband, Kavous Seyed-Emami, in Evin prison.鈥

Mehran said his mother appreciates the Canadian government鈥檚 involvement and that she was pleased to receive a personal phone call from Freeland herself.

鈥淸That] gave her further comfort and further reassurance that the Canadian government has prioritized this issue. It is on top of their agenda and they鈥檙e doing their absolute best to get my mom home,鈥 he said. 鈥淲e really believe that this is the case.鈥

Although he doesn鈥檛 know if Iranian authorities will listen to the Canadian government鈥檚 calls for action, Mehran said he hopes the international attention on his family鈥檚 case will pressure the Iranians to provide answers.

鈥淲e don鈥檛 want a single day to pass where there鈥檚 no action happening and nothing is being done to get her home,鈥 he said.

Mehran said his family will probably have to wait two weeks until the holidays in Iran are over before they receive an explanation as to why his mother鈥檚 passport was confiscated.