oil dipstick bolt broken on 86 SN 2001

I let my nephew take my boat out a few weeks ago and when it came back the dog house was lifted up a little. I noticed that the oil dipstick was protruding from the bottom of the dog house. I bent the dipstick tube back up and really didnt think about it much after that. Probably put about 15 hours on the boat since then with no issues. I took it out this evening and noticed that the bold the holds the dipstick to the motor mount was busted off. It appears to have sheared the bolt with nut (has a hex head) and was sitting on top of the motor mount. I think there is enough room on whats left of the bolt to remove it if its possible. Has anyone replaced this part. I can provide pictures if needed.

Philip