It is unlikely but not completely uncommon for a Speaker to vote in favor of the government on a confidence motion such as the budget. One example we can draw from is in 2005,  in our Federal Parliament, the House of Commons, Paul Martin's liberal minority government introduced the budget and at second reading, the budget vote was tied 152-152. Speaker Peter Milliken, was the tie breaking vote. He voted to pass the budget, as the Speaker's role by convention is for legislative debate to continue. Paul Martin's Liberal minority government survived. However, I will highlight I do not think it is convention for the Speaker to be breaking a tie every single time a bill needs to pass. I think a new election should be triggered, to either give Mr. Horgan, Or Ms. Clark, a clear mandate to lead the province instead of being beholden to a 3-seat caucus.