"I know my position can replaced after the 12 weeks but what bothers me is when I contacted my manager for return he told me "You need to get your doctors to sign off on long term disability". By the end of the conversation it was clear there was no option of return." As you said above, once the 12 weeks of FMLA were exhausted, they had no obligation to return you to work. It appears your manager was attempting to make a helpful suggestion, albeit not in a tactful or even helpful way.
"On top of all that the bank still has me listed on medical leave so when I tried to get a hardship withdrawal from my 401k I was denied." That doesn't make sense as hardship withdrawals are designed specifically for individuals who are currently employed. Your request for a withdrawal would have been denied if it didn't meet the very limited criteria IRS reg's allow however.
If your employer refused to grant you four additional days of leave BECAUSE you have a disability and they want to be rid of you, you may have a discrimination claim to bring, particularly if they've ever granted additional leave time to anyone else who exhausted their 12 weeks of FMLA. I suggest you speak to an employment law attorney