Squamous Cell and Lung Transplant

Hi. I hope it is okay to post here. My husband is the patient but does not go online. I need info.

He had a lung transplant 3 1/2 years ago. He has done pretty well until his skin cancer (face) metastasised. Now he has a second tumor in his peretoneal cavity. 

He has decreased kidney function, so could not have the chemo that would normally be done with the radiation he had to his face and neck. 

With this second tumor, we are learning he can have a different kind of chemo agent. However, he is weak and needs to gain weight and get sronger first. So far he has gained a little.

Are there any transplant patients on this site that have had this expereince or anyone who can  shed any light on this?