Depends on what industry you are in, but you may just be able to pick up the work/contracts without buying the business if customers know he is up for sale…
Other option would be to pay some upfront and defer the rest (maybe dependent upon trade) however, the vendor will prefer cash upfront for obvious reasons.
Credit lines are tough at the moment without security, there may be some grants out there – speak to you local business link who maybe able to point you in the right direction.