As many celebrate news of President Donald Trump's groundbreaking hostage release deal, the father of the youngest American still in Hamas' captivity remains cautious."It's a mixed bag of emotions," Ruby Chen, father of 19-year-old U.S.-Israeli citizen Itay Chen, said Thursday on "Fox & Friends.""There's the excitement, finally having hostages coming out, anticipation, but also anxiety because it's not 100% [certain] that all the 48 hostages are going to be coming out, so there [could be] some that will be somehow left behind because they will not be able to find them."TRUMP SAYS 'WHOLE WORLD CAME TOGETHER' TO SECURE ISRAEL-HAMAS PEACE DEAL AFTER MONTHS OF DEADLOCKChen's son was originally thought to have been kidnapped during the Hamas terror attacks of Oct. 7, 2023 while serving on the Gaza border, but he was later declared dead by the Israel Defense Forces (IDF). His body, along with the remains of multiple others, is still in Gaza and is expected to be released in conjunction with living hostages as a part of Israel and Hamas' agreement to phase one of Trump's peace deal. Chen, however, said his family is still waiting to receive confirmation that Itay is one of the remaining U.S. citizens who will be released. He added that there is no physical evidence to indicate what happened to his son so far.TRUMP THANKS GROUP REPRESENTING FAMILIES OF HOSTAGES FOR NOBEL PEACE PRIZE APPEALBecause of that, he maintains a sliver of hope that Itay somehow survived."It's been a battle ever since to just get the simple acknowledgment from Hamas, this terrorist organization that did not even acknowledge, to this day, that they have him in their possession and what his physical status is, and the previous administration was not capable of getting those two indications," Chen said."We have high hopes with the new administration, with President Trump. God bless him for doing what he did and focusing on the hostages."Alex Plitsas, formerly of the White House hostage policy team, expects approximately 20 of the remaining 48 hostages to be alive.He told "Fox & Friends" that senior officials from Israel and the U.S. said Hamas had requested extra time to try to locate the bodies."The living folks were easier to find but, due to the military activity over the last two years and recently the heavy bombardment, they claimed to have lost contact with a few folks, so they needed some time to make that happen," he said.President Trump said he expects the remaining hostages to be released on Monday.