Took my Cossie for a service and wanted the break fluid changed as it aint been done for 4 years!

Bloke at the garage said that the nipple on the calipers was seized and he didnt want to attempt to release it to change the fluid in case it broke!

As i`m not mechanically minded in any way just wanted to know if he was bullshitting me because he didnt want to do the job or is he correct, the nipple might break?

If so what are my options? Worse case, new calipers?

Cheers

Lee