Question about drug test after work injury

Hi,

My friend got a minor injury at work last night. His supervisor asked if he wanted to go to ER, and my friend said no.

This morning my friends foot was in pain, and he was having trouble getting around- he called in and said he’d be back tomorrow. They called back, and told him to come in, and they were taking him to hospital. He said he didn’t want to go. He said he was feeling better after already resting majority of the day. They said he had to.

He went into work, and told them he was fine now. He said he wasn’t filing a claim or suing them. He said he’d be in tomorrow. He’s worked there over a year. It’s a union position. He never misses work. He said he’ll use one of his points for missing the day, and that he’s fine now. They took him to the hospital anyway.

He got X-rays, and is being paid today and also tomorrow too. He’s supposed to go back to work Monday as usual.

Issue- they gave him a drug test. He’s not on an illegal drugs. He does take Gabapentin a few days a week though, smaller amounts. He has a lot of pain, and his mom gives them to him. He hasn’t gotten his own, because his insurance isn’t the greatest. He also hasn’t needed to. His mom takes them regularly, but gets plenty extra. She started giving them to him when he started this job because it causes his pain to flare up especially when he has 12hr shifts.

Will the hospital just test for illegal substances? Like typical recreational drugs? We just hope the Gabapentin doesn’t show up, and that if it does- that they don’t flag it and ask to show proof or prescription. He’s on one controlled substance that’ll likely show up, but he has a prescription for that.

Thanks for any help! Also if there’s any other groups I can ask this in, I’d appreciate it. Hope this is okay to ask here. Thank you.