Mike Hutchinson is correct - once bankrupt the assets will vest in the Trustee and will be realised or disposed of. If there is value to the business then they would look to sell on the open market or back to your boss (obviously he would have to find the funds elsewhere as he is bankrupt). Failing this they would arrange for it to be wound up and any surplus funds paid into the bankruptcy.
If it sold to another party then they will probably want to control who the directors are.
As Mike says your boss will be unable to act as director whilst he is an undischarged bankrupt unless he seeks approval from court.
In terms of your position if you accept the directorship you will obviously have the normal director's repsonsibilities and liabilities. I would also be careful that this is not just an agreement of convenience with your boss continuing to make the decisions in the background. If he is he may still be committing an offence by acting as a shadow director and this could have implications for you.
If you do decide to take the role ensure that you are fully aware of what you are getting yourself into - make sure you know what the company's financial position is and the relationships with the other entities.