It concerns me that your mother seems unwilling to get him veterinary care if he needs it. Can you have a conversation with her about how important that is, as part of being a responsible bird owner? It's almost inevitable that you will need to take him to the vet at some point, so if you anticipate problems with this, then I urge you to work out a plan now, so that you have resources and options in the event of an emergency. Its really painful for everyone involved when we have younger members here who know their birds need medical care, but are unable to get it because they are dependent upon their parents.