I've raised £500 to buy Dylan an exercise bike and to put towards a new wheelchair

Dylan is my nephew. In July last year Dylan was playing on a tree swing and he fell off it.
As a result of that fall, Dylan is now wheelchair bound most of the time.
This freak accident compromised the supply of blood to his hip joint and his hip bone has perished. Dylan is 14. He can't have a hip replacement until he is fully grown at 25.
Dylan is now unable to play football and run around. He has had to miss out on school trips and days out with his mates. He is in a considerable amount of pain most of the time.
Dylans hospital consultant has said that riding a bike could help. Riding a bike would be good for him both physically and mentally. The risk of going over a bump and falling off a bike is too high though.
So, with the consultants blessing, I want to raise enough money to buy Dylan an exercise bike. A really good one. A static one that will sit in his house that he can use regularly.
In exchange for donations, I am going to swim 2 kilometres. That is 100 lengths of a 20 metre pool. The most I have managed to do in the past is 40.
I will swim this in the first week of June - I need a few weeks to get my fitness levels up and to practice swimming (I am not a natural swimmer and have never had a swimming lesson!).
We would appreciate your donation so much.
Thank you :-)