My mum has just had a breast cancer operation

Firstly my best advice is to get your mother to join this forum as she can speak freely to other ladies in same position as her.  We often hold back on worries/fears to close family and friends for fear of upsetting them.

It's normal after anaesthetic to be washed out for a few days or weeks even.   She might even not be sleeping at night as she's worrying.   You don't say what surgery your mother had.  Did she have WLE (wide local excision, often called lumpectomy) or mastectomy and did she have nodes removed?  Recovery from just WLE is usually quicker as less invasive surgery but can be issues with all surgery.  What tablets is she on.  I didn't require hormone therapy so can't advice but there are other ladies on this forum who take them and will talk to your mother about possible side effects etc.  Radiotherapy will take place once wound has healed.  Has she had biopsy from surgery results yet?  They biopsy tissue taken and results are generally about 2 weeks which inform next stage of treatment as it can change.  Radiotherapy she needs to ensure skin in good condition before as minimum treatment is 5 consecutive days (sometimes break for weekend).  Most women suffer just a sunburn effect and unit will recommend creams at planning meeting before treatment starts.  Mean while once healed she can use a gentle moisturiser like E45 to ensure skin in good condition.  During, after treatment Aloe Vera gel kept in fridge is nice and cooling if she has any burning sensation.  It's important to be well hydrated too so upping water drinking now and drinking plenty during and after treatment will help but fatigue is normal during and after radiotherapy.

The biggest hurdle for most people diagnosed with cancer though is the mental impact.  Even though they may be strong, sensible people it can hit them even months after treatment has finished.  She may find people are dismissive of her diagnosis.  They do it from a kind place or to make themselves feel better,  normally saying "well you are fine now, they've removed the cancer etc"  or a simple "oh you'll be fine".  It p!sses most patients off though as mentally it's been a big deal hearing they have cancer and they don't want to be dismissed.  They need to grieve their "carefree" pre cancer life.  So let her talk if she wants to, but if she doesn't want to burden you or you feel she's putting brave face on tell her you've been recommended she joins this forum to talk to women who have been or are at the point she's at.   You could just send her a text with a link to the forum which she might use when the nighttime worry gremlins keep her awake.   There's no such thing as a silly question, there's no such thing as an irrational fear etc. here; just a warm welcome and understanding.