re: Intellectual Property when leaving a job...

Pretty easy to do a patent search on the Internet and see if he is telling the truth. Just do a patent search for his name.

Honestly if you have something to do with the patent or were part of the development team for the patent then you are stuck. If you are just a technician and used the thing then the only trade secret you have is your training. Which is meaningless unless you go after his clients and he can show damages via lost revenue

Just working somewhere and being trained is not a confidential situation it is merely a trade secret that is void once someone with the training leaves.

Not signing a non-compete is far more important than signing a confidentiality agreement. Remember his lawyer will have to prove what you learned is legally confidential and you caused damages after you left

Definitely talk to the new company, their IP attorney will vet your situation and give you facts not speculation. If your old boss is lying they will know pretty quickly

You want to be a standup guy and be honest, don't hide anything