I have had special needs buns re-homed to me.
Check on the size of the house- a bun prone to sickness/special needs can need to be a house-rabbit esp if they have a condition that can quickly go down hill.
Check their vets- mine whilst not in the upper ranks of Bun savvy is very bun aware and offers bun dentals in a specialist dental suite and 24/7 emergency care locally. It also has a hospital with nurses who have specialzed in rabbit care and a rabbit savvy vet they can call in. The greater the special needs the more important the quality of the local vet.
Check they have thought ahead of the vet costs and can pay. A pre-existing condition is often excluded from insurance.
Check the rabbit accomodation and they are aware of the costs needed.
For example for Pumpkin - dental bun with poor sight.
FOOD.
Hay bale per week £3.50
Alfalfa King Timothy £7.00
Mixed dried herbs [winter]p.w £7.00
Small amount SS pellets £1.00
Fresh veggies [winter] p.w £5.00
Large willow ball to chew p.w £5.00
Megazorb [bag lasts for quite a while]
VETs
Dental when needed with G/A £100.00
Dental and duct flush with G/A £150.00
Critical Rabbit Care [hospital] £45.00 p.d
Myxi & VHD vaccins £70.00 p.a.
HOUSING
Large indoor dog crate £100.00
Large single story hutch £250-450 depending on make.
Large puppy play pen high sides £80.00
Sundries inc bedding, snugglesafe, bun first aid box with emergency drugs, toys and a rabbit carrier that can secure into a car.
I really do mean it when I warn people a rabbit costs as much as a cat or dog to keep well and happy.
And check the prospective owner is an experienced rabbit owner with good knowledge. A special needs bun is not a good first rabbit for someone who has never had a rabbit before. The greater the rabbits needs the greater the need to ensure the prospective owner can cope. It would not be fair on either the bun or the possible owner if they do not know what they are taking on.