The 14-year-old visited the club's training centre in Carrington during trials in October, and impressed United staff who plan on signing the forward.
Malmo had hoped to retain the services of the teenager, but Brandrup has resigned himself to the fact that Gomes will move to the Premier League club.
"Lucas was in Manchester for week 44 and unfortunately I do not think we’ll keep him," Brandrup told Skanesport.
"He moved here from Karlskrona in the autumn of 2016 to go to our sports school and, of course, he might have to wait until he left the school before moving back.
"But I understand he’s impressed with United.
Gomes joined Malmo last summer from FK Karlskrona, and ahead of his trial match in England, told Ungdomsfotboll that he was really looking forward to testing himself with the Red Devils.
"It will be a lot fun and I will trial as well as play with them. I think there will be a higher pace there but I hope and I think I will handle it. I'm looking really forward to this adventure."