Methadone and post surgery pain management - 7oh?

I have a family member that is in severe pain after a dental surgery. They have been on 80-90mg of methadone for many years. Is it safe for me to give them 7oh for some relief? I used to use 7oh and have some leftover from months ago and just wanted to know if there was anyone out there that is on methadone and has successfully and safely used 7oh for post surgery pain. Thank you!