If he goes to Settings->Account->Billing Information will allow him to check if it is currently set to your card and if so change it.
If you brought it as a gift subscription wouldnt have thought it would renew automatically though.
You do have to watch strava as they auto-renewed my premium subscription with no warning that it was due for renewal and the payment would be taken. Then then ignored my request for the renewal to be refunded - this was the day after it had been taken.
