His problem has been mainly with math. But over the last few weeks, as I suppose is normal for kids, he has worked some of it out. Some of the topics like subtraction seem to have just clicked! Oddly enough, his Spanish is the least of his problems, wish I could say the same for my husband, the only one in the family who can´t speak it!

I don't completely have that situation, but we did experience having our daughter in a foreign country. She was right at age 1 when her language was first developing. She could speak French with a perfect accent, but was slow to grow her vocabulary in total. I had heard that is normal when a child is learning two languages. I still think it's great for them to learn two languages at a young age, though, even if it means slower learning in general.

Maybe you could nudge him towards more independence with his learning and homework slowly? If he is used to help, he is probably starting to rely on it too much.. but it would be a shock to go to the other extreme too quickly. Much encouragement when he is doing something right would also probably help. Perhaps he is losing some confidence since others speak Spanish as a native language.