Cover/seal inground pool ancient broken light fixture

[IndianaDoria]

HELP! My elderly parents are in process of repairing pool to complete sale of house. The 1971 concrete fiberglass pool still runs great, but the broken & disconnected light (electrical problems back in the 70's) has become an algae farm. Whatever their reason for not properly dealing with this fixture, I THINK that I must seal the niche at this point. Buyer's pool inspector said to just leave it alone, buyer still is negociating for a complete repair. I remember as a teenager water half-filling the fixture, plus getting light shocks touching the light fixture, and the wires were yanked out back then. Sometime ago the lense broke, one edge of broken glass remains. Suggestions please.

[Denniswiseman]

If the buyer still wants the light negotiate with him and reduce the price for him to fix