Help for a friend leaves going brown then stems then they die off

[Grownespeciallyforyou]

My friend doesn't have net access and she has asked me what the problem is so hoping for some advice. This is what she has emailed me "help!....The plants have got something!! The aubergines and courgettes' leaves are dying (going brown) on the edges, then it hits the stem. It's killed one of the aubergines, one courgette and a tomato already - what have I done?! Aubergines and toms are out in day and in at night, courgettes are in veggie patch but covered at night if it's cold. She brought her plants from a local garden centre.

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to me it sounds like some virus, but what? any way to ericate it?
thanks to anyone that replies

[taff]

location? in the uk? If so, aubergines like it warm, very warm, you need to get varieties specifically for this country to have any hope of fruit. They shouldn't be out at all in this weather.
Courgettes - only plant out when all frosts have passed. They will die if frosted whether they're covered or not.
Tomatoes, no idea, it's not that cold for them, they wont grow, but going brown is either a fungus, a mould or drying completely.

what are they planted in, have you got pictures?

[Two_Sheds]

Overwatering?

[Grownespeciallyforyou]

hi thanks for your reply she will send me photos then i will upload them. location Cambridgeshire. The varieties are for UK growing like black beauty.