Many thanks for the reply.
Yes he did have bad lymphodema last year, one leg was badly swollen for months but after his palliative radiotherapy in December the leg swelling has disappeared.
We are not aware of any heart issues. The doctor just mentioned fluid and getting an x ray and then maybe draining the fluid...
I just wondered what caused the fluid but I guess we will know more after the X-ray.
Its just a shame, as he was slowly enjoying getting more mobile the past month or so but now suddenly a lot more breathless.