Passport water damaged - Need help with the options ?

[123kk]

Hi All,

I am applying for my in-laws visitor visa. Most likely only my mother in-law will be coming but I am also planning to apply for father in-law as I think that will improve chances of getting visa for my mother in-law ( thats what I have heard\read). If thats not true, I can simply apply for only mother in-law ?

My father in-law passport got damaged by water some time back. Details are readable but not the photograph ( though he has a photocopy from before the damage)

Can I still fill his application based on damaged passport and then he can still take damaged passport to the interview ?
Or he needs to apply and get new passport first and then fill application.

Thanks

[Jot18]

If you can't see the photo, I would recommend applying for a fresh passport before you start the process.