Chemo options for Undifferentiated Pleomorphic Sarcoma (UPS) lung mets

Hi - looking at options for my Dad
He has UPS which was diagnosed following removal of a mole on his back - he has bilateral lung mets, the largest now 35mm. He was on Trabectadin for over 2 years which was great with no side effects for him but this was stopped following progression of the lung mets. He then tried Pazopanib but liver results too high so was stopped. Was then left on ‘watch and wait’ which just showed more progression. We chose Trabectadin as first line as we thought Doxorubicin would be too harsh (he’s 79) but wondering whether to give this or any other chemo a go? Consultant is just suggesting to focus on quality of life but my Dad is willing to give anything a go. Difficulty is he also has diffuse pleural thickening (asbestos related but is not mesothelioma), any thoughts? Thanks x