Legally, you can buy as much insurance as you can afford and as the insurer will sell you *after full and honest disclosure* of medical conditions or anything else which you are asked about on the application for (or to increase) insurance. In other words, you and your boyfriend can't hide the tumor if asked about medical conditions, operations or treatements he's had, etc.--hiding it, if it's inquired into either specifically or as part of a general evaluation of medical condition--would constitute insurance fraud. On the other hand, if there is full and accurate disclosure, then you can buy whatever level of insurance they'll write for you. So the issue is simply that you have to be truthful when applying.