Algebra struggles and what to try next

[alltogethergarza]

Hi all! 
My son did Shormann Algebra I last year and is going to finish Algebra II this year. This program includes a 1/2 credit of geometry each year. He struggled in Algebra I, but for the second half of Algebra II, his daily grades have slipped into the upper 70s- mid-80s. I am not 100% comfortable with him moving on to PreCalculus next year, but it is not as if he flunked either. He is resistant to "mom" helping him too much and I am trying to respect that, but I have maybe let his struggle go on too long. What do you think, homeschooling friends? Any advice as to what to do next?
(He is considering going into engineering or a science field so going easy on math is not an option )

[Mom0012]

Maybe look at Khan Academy and spend a few months going through the algebra I and algebra II material until he feels solid on it?

[lmrich]

Go back and do another Algebra II with him. It will make your lives so much better. Work through the summer if needed. 

[freesia]

How are his test grades? If they are  fine and you go over missed problems, I wouldn’t worry. 

[BusyMom5]

It would depend on the reason for the grade slippage.  If it's the geometry,  you could do a different geometry program.  If it's the algebra, I'd have him redo it until he has the material down.  If it's messy work, poor attention to details, relying on the calculator, ect. I would focus on that, but not hold him back.