It varies depending on where you live. Gliders are considered exotic pets so their vet care may cost more than a dog or cat would.
You can call vets in your area to find ones that have experience caring for Sugar Gliders and ask what the cost of a well check up and fecal testing will be. The vet can trim nails also - some may charge a fee but most do not.
You would then be able to tell your father how much the cost will be.
You may also want to find out the cost of neutering your male. At some point it will become necessary. If you allow your pair to breed, and if you plan on keeping the joeys, you will also need to neuter all the males (including Dad) if you plan to keep the gliders all together.
If you do not neuter the males - Dad will try to mate with the female joeys. Any male joeys will mature about 4 months OOP and then mate with their mother and with any sisters.
Without neutering - if you keep all of the joeys you will need 3 cages - one for your breeding pair, one for all the female joeys and one for all of the male joeys.
For the cost of the additional cages - you could neuter you male before your glider population explodes.