Can a solicitor withhold funds?

[Lizalita]

I am joint executor of my parents' estate. We have grant of probate, bank accounts are closed, we're just waiting for a share portfolio to be dealt with and should be able to disburse funds. Beneficiaries are myself, and 3 siblings. Problem is, one of siblings is having some major mental health issues and has been sectioned recently (has just today been released from section but is still an inpatient in a psychiatric ward. He has been quite abusive to all of us including solicitor and is pretty desperate for money. Solicitor is saying that it is 'too risky' for his firm to make a payment to him whilst he's still sectioned. I can't find anything about this online whatsoever, is he right that the firm can just say no, they're not releasing any money to him? Myself and the other executor would like to release money to him as we feel it is his only chance of getting 'better' and getting some stability. He is effectively homeless and jobless right now. Thanks in advance for any help!*