I may just be tired, but it seems like you have a lot of complicated things going on that make it a little difficult to provide good guidance. Here are some of the things that are tripping me up.
First, is your rental properties actually a good investment? I don't know much about real estate, but I've very often seen people on these forums post the details of their rental properties and have knowledgeable forum members explain why they'd be better off selling and investing that money in the market. With the limited numbers I see here I suspect that might be the case for you. It looks like the gross income from the rental is $9k / year, which isn't a lot, and the upkeep and other costs increase your monthly spending. I would very strongly recommend posting a question just about your rental property in the "Real Estate and Landlording" section of this website. You might find that it's a great investment, but you might also find that this might be a great time to sell it.
You may also want to do the same thing with estimates for the house it sounds like you're currently living in. The main reason I'm posting this is that two houses worth $460k should (I think, again I'm not an expert) be generating a LOT more than $20k / year. It looks to me like these are not good rental properties, but the good mustacians in the Real Estate forum will be able to give you better advice than I can on that topic.
Specific Question(s):
Base on current saving rate (30%) if it is possible retire in 10 years between 48 to 50 ? Based on x25 and 4% rule, it will be at least 1 million. The plan is to take 401k after 59 ½ . SSN @ 62 is 10k per year. I do not know if 1 million is 401k+Roth+HSA or all the asset (includes property).
The $1 Million as based on your invested assets and should not include the home you live in or any rental properties. They are treated separately because the 4% rule of thumb comes from a mix of stock and bond investments. Rental properties vary tremendously in terms of the income that they generate as well as the costs for maintenance, property taxes, and vacancies. Some great Real Estate wizard may be able to generate a long-term, consistent income of more than 4% of the rental properties' value, while other RE investors may barely generate any income at all after expenses.
To do the math properly, it's important to get a good estimate of your expenses after you FIRE. I assume your expenses will go down after your child is out of the house. If you're living at your parents' house then your expenses then might only be $20k / year or even less. As long as you'll be able to maintain that (or whatever your expenses will be) after they pass, then your number might be lower than $1M. Anyway, after you have a good handle on your living expenses when you FIRE then you need to figure out how much income you will be able to count on from your assets. Again, treat rental properties separately from the investments that are in the market. The people on the Real Estate sub-forum can help with that. Assuming the 401(k) money is in the market (it isn't listed as "stock" like the Roth and HSA are, so I'm worried that money isn't invested) then take 4% of that to get the income from that portion of your assets.
Here's an example of how the math might work, but keep in mind these are just my guesses for your numbers:
$40k income required.
$20k rental income reduces required income from other assets to $20k
$20k required from investments (other than rental properties) = $20k * 25 (from 4% rule) = $500k invested assets required
Note that if you were to continue to work your side business, you could quit your day job as soon as you move into your parents house and the rental income increased to $20k because your side business is bringing in $24k and could bring in $36k. I'm not recommending that because I don't know the stability of your side business and it would lock you into continuing that long-term (longer than 10 years). But I think it's nice to know that you aren't tied to your current day job if you don't want to be. Side business income is incredibly valuable even if it doesn't bring in a huge income.
I still can work part time but most time will spend with my parents and take care of them. At this period, the living expanse will be lower since I will move to parents’ house. Rental income from two properties ( estimate $20k per year by current market).
Health expanse is unknow. Do not know how to estimate it.
Health care costs are very easy to estimate! There are a ton of calculators online you can use, but there are some tricky bits. One is that costs and thresholds can vary by state. Second, your income dramatically impacts your options and costs. If you make too little, you'll end up on Medicaid. If you make too much, you'll pay the full cost of your insurance. Many people who FIRE try to keep their income to somewhere around 1.5-2x the federal poverty rate to get the best deals on health insurance. Note that income does NOT equal spending! Some people spend $100k / year but generate income of $30k / year to keep their health insurance and tax costs down and make up the difference from their taxable accounts. It's a game, but after you learn the rules it's an easy one to win - although it does take some planning. I'd be happy to help figure out an estimate of your health care costs if you want help and if you let us know what state you plan to FIRE to.
