I think two reasons the Lions are re-signing Oday Aboushi are he performed better than anyone could have realistically expected late in the 2019 season and his familiarity with the Lions Offensive blocking system ( as well as familiarity with coaches ). The latter is that much more significant in 2020 than in a typical year because of the limitations the Lions will have in the off-season due to the Coronavirus situation.
Assuming the contract is heavily team friendly, the decision to re-sign Aboushi would at least be understandable.