Question

Hello Rabbi,
My 6-year-old son started first grade and spent one full day there before he had to go into quarantine.
According to the guidelines, he is supposed to come out of quarantine on Tuesday at the end of the day, which is the first day of Rosh Hashanah. In order to leave quarantine, he needs to take a test on the eve of the holiday.
The results will not be received until after the holiday begins. In the Rabbi's opinion, is it permissible to check the results during the holiday so that he can at least be released from quarantine for the second day of the holiday?
On the one hand, it doesn't seem right to me to keep him and the rest of the family in quarantine on the holiday, as against using an electric device on a Jewish holiday. This is of course from the optimistic perspective that he is negative. You could also consider the pessimistic side, that he is positive, so perhaps there is also an argument of saving life in order to know as early as possible?
Wishing you a good year.