Medical expense claim

Husband receives WCB Pension which he was granted a large amount of in late Dec 2018 for dental procedure. Due to timeline it was received (Christmas/New Years) Surgeon/practicioner was unable to due procedure till early Jan 2019. Now we have a huge "income" ($30,000.) increase to our low income (aprx. $30,000) and may lose needed benefits if we can not write off this expense ($29,000) 

1)  Is there any way we can claim this expense despite it taking place in Jan 2019? 

We do not estimate our income 2019 will be much more than current aprox amount. 

2) If our annual income is around $30,000 are we able to claim $29,000 expense? 

3) can we even claim that much of an expense!?!?!

Thanks in advance