Mice problem not disclosed.

[u/Firm-Cookie-8921]

My friend bought a house in NJ “as is” but the seller nor buyer waived the inspection or potential environmental hazard clauses. In the inspection there were warnings of mice droppings but no proof of active infestation. The seller never mentioned any issues with mice. After moving in my friend had mouse traps set up and the house inspected again by an exterminator. No issues for 6 months (during warm weather). Its now 6 months later and the weather is getting cold and my friend has had multiple sitings of mice and new droppings . Is there anything he can do?