SOLVED. Childrens or YA - boy named alistair finds magic/alternate reality friend goes missing he gets stuck there

[Jessica]

This book is about a boy names alec. His friend or sister goes missing in the timeline of the series. There is magic and a river involved and also an alternate reality. He gets stuck in the reality and he thinks it's been years but when he gets out it hasn't been very long. I think there might be a bird in the alternate reality but could be wrong. In the alternate reality there's just water and nothingness but I think he is able to create whatever he wants and also might meet another girl there. I read this book somewhere between 2012-2018. The cover of the book is either blue, green, or purple but it's a series so I'm not sure which color the first book is. Also in one particular part of the book it is winter and Alec just stays in his house because I think his mother passed away and at some point he goes to a room with his moms stuff in it to remember her.

[Jessica]

My sister finally remembered the book. It is called The Riverman and the main character is not alec, it is Alistair.

[Rainbowheart]

Glad you found it!

The Riverman for the link.