Can Metformin Be Taken While On Levothyroxine And CoQ10?

Can you take Levothyroxine, thyroid medicine if you also take CoQ10 and can you also take metformin with these....my Mom has diabetes 2 and takes those two medicines, plus insulin sometimes when needed---but would like to take CoQ10 for arthritis in foot? Thank you in advance, Susan my email is: YYYY@YYYY