Since there was no previous record of hemophilia in her ancestors, Victoria must have suffered from a mutation. Victor would be a hemophiliac, and is rather unlikely to last as long as a monarch and may not even live long enough to reign. Using examples from Victoria's descendants, son Leopold died at 30 and his grandson Rupert died at 20. Other of Victoria's grandsons and great-grandsons died at 2, 4, 19, 31, 32, and 56 from it.
If Victor dies as a child or before he fathers children, Ernest Augustus becomes King of England as well as Hanover. On his death in 1851, his son George inherits both thrones, but I'm not sure if England would be willing to protect the throne of Hanover in 1866.
Victor's hemophilia is because of a problem with the X chromosome, thus all his sons will be free of it and all of his daughters will be carriers. Hemophilia still spreads to other royal houses in Europe.