How to cope after loss from suicide?

Trigger Warning!!!!!

Suicide, Loss and Grief......

Hi Everyone,

I'm writing on behalf of my family, who are looking for comfort/advice/support from people who may have the devastating experience with a loved one who has taken their own life.

A bit of back story....

My sisters 17 year old daughter, my darling niece took her own life early last month.............
She was my sisters baby girl, her best friend and her world, she was a big sister who was her little brothers world too, she was adored and loved by all her family and friends and we're all having such a hard time coming to terms with her absence from our world.

She didn't leave a note, she had a fight with her boyfriend not long before, so we believe she didn't mean to do this, she was caught in the moment and perhaps even hoped he'd find her in time... this breaks our hearts so much, we know it wasn't what she wanted, we know she wouldn't of wanted to do this to her mum, dad, brother, family and friends...

We're so worried about her mum, my sister....

How do we move through this grief? How do we support her? Some words of advice, experience, comfort, love would be much appreciated...

Thank you