Sunburn or fungus,please help total begginers

[Alexa_ion]

Hello everybody,

I am trying to help my father who has some problems with two of his flowers.Two of the plants have begun to show some worrying dark spots on the leaves and sume discoloration .I need some help with what the best treatment would be and maybe how to prevent this from happening again.We are total beginners on this subject,any help would be greatly apprecited. Also i am not sure the pots he uses are ok.
I will post below a photo with all his plants with numbers so we can identify them easily,to see their position and pots.And afterwards with the two specimens that have problems.Can you please help me restore them back to health and improve their well being









?

Thank you so much

[Ray]

Sunburn.

That first close-up was "iffy" for me, but seeing the tell-tale "parchment" appearance in the others gave it away, making that other one likely.

[Dollythehun]

I wanted another opinion first but I agree.

[Alexa_ion]

Thank you very much for the reply,i will ask him to move them from that area .I am glad it is not fungus or bacteria

---------- Post added at 02:00 PM ---------- Previous post was at 02:00 PM ----------

Thank you for the answer,i will change their position today.

[syspila]

Sunburn for sure!

[Roberta]

A sheer curtain may be all that is needed, to soften the sun light. (What direction do those windows face?) The overall amount of light is probably fine, but at certain times of day there must be a direct "hit" that produced those toasted spots.

[estación seca]

Agree with burning. But - have you turned on the heat yet this year? The plants are directly over the radiator. Rising heat could also burn them.

The plants look like they have been in those pots quite a while. Most bark medium lasts 2-3 years at most. Especially for some of the plants that seem almost out of the pot, it might be time to repot into fresh medium.