In your shoes, I would not accept a contingent offer with no sale of the buyer's house on the horizon. If the buyer's house were in escrow and there were no other offers on the table, I might consider it. Not in this case. This is not a buyer. This is a dreamer.
Your agent is supposed to represent you. Why would s/he recommend accepting this offer? Is the price too high? Is there something wrong with the house? Is your market extremely slow and nothing is selling? Otherwise, the recommendation makes no sense. The buyer can keep your property tied up for months and then just walk away.