If he has home buildings insurance with accidental damage then yes he can claim.
If so, the best thing to do is ring up the insurance claims line to notify them of this incident, they will advise him to obtain estimates for repairs, then if quotes are reasonable, they will authorise him to go ahead with repairs and forward insurers the final bill. (Usually).
If the repairs will not amount to very much, your relative can either withdraw the claim and pay for repairs himself, or he can proceed with claim and will have to pay the policy excess which is usually �50 or �60 (check policy).
Provided he has not made many claims, and the bill is not too much, this shouldn't have much of an impact on future premiums, but your friend must ensure to disclose the claim on future home insurance.