YaYaJen, I hope GS's appointments go well and once you know the degree of deafness, he is able to get the support he needs, both medically and educationally. I hope Gotthetshirt's grandson is doing well, too.
I have personal experience of living with a deaf person, and also know two people who have worked with deaf people in their professional lives.
My husband was born in the 50s with a congenital hearing loss. He had hearing aids (box on chest when a small boy) and speech therapy, went to his village primary, passed the 11+ into grammar school, went to university. He too is a professional, picked up a foreign language when working abroad (a challenge for a deaf person, as you can imagine), and is also an author. His deafness hasn't stopped him doing anything he wanted to, apart from join the army, which he would like to have done when younger, but he was deemed medically unfit.
My husband's parents were insistent that OH should go to "normal" schools - they didn't want him segregated. However, they also made decisions that OH now regrets - he was excused from languages and music on the grounds he couldn't hear well enough, and he wishes he'd been encouraged to do both now, especially as he had a job abroad for a while and had to start language study from scratch.
We have a friend who is a teacher in a deaf unit attached to a primary school. She signs with a lot of her children. From this friend and from my husband' experience, I know that it's absolutely possible for deaf children to do well in their education and to enter a range of jobs in their adult lives. It is vital, though, to push for the right path for your GS - be it "normal" school/deaf unit; implant/non-implants; sign language/speech/both; even hearing community/deaf community.
Finally, DD worked as a carer with adults who were both blind and deaf. Their needs were profound, as communication had to be through touch-sign, and their worlds were pretty much restricted to their own small community. Sadly, in most cases their parents/siblings hadn't learnt sign, so they had limited contact with their families. Whatever your GS's needs turn out to be, it is so important that the rest of the family get on board, and if he is taught to sign, that the rest of the family do too.
Wishing you well....