An HSA is owned by one person only. No matter who gives money to a person to make contributions, only the owner makes the contributions, and the owner is responsible for all tax consequences.
You can use your HSA to pay for qualifying expenses for yourself, your spouse, and your tax dependents. If your BF is your dependent, you can use your HSA funds to pay for his expenses.
Your BF can't contribute to an HSA if he can be claimed as someone else's dependent. Even if you decided not to claim him, he must check the box that says he can be claimed. Failing to do this would result in him receiving improper tax benefits and could be considered tax fraud.
Your BF needs to file a tax return this year. He must report the HSA contributions. If he leaves the contributions in the account, he will be assessed a 6% penalty this year and every future year that the excess remains uncorrected. Or, he can have the excess contributions removed by the HSA bank and returned to him, before the April 15 deadline. But this must still be reported on his tax return. If he does not file, he may receive a bill for tax and penalties for the excess contributions. Also, if he does not file, the excess contributions in the account may be subject to additional taxes and penalties in the future, since the IRS will not have a record of how he corrected the excess contribution issue.
